AI Trajectory

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Seq	Timestamp	Type	Name	Duration
0/0	2026/09/18 03:16	flow	patch-triage	2m Args: null Results: { "EnableConfigs": [ "CGROUPS", "MEMCG", "MEMCG_V1" ], "FocusSymbols": [ "memcg_write_event_control", "memcg_update_tcp_max", "mem_cgroup_swappiness_write", "mem_cgroup_oom_control_write", "mem_cgroup_oom_register_event", "__mem_cgroup_usage_register_event", "memcg1_oom_recover" ], "KMSANReasoning": "This patch is a mechanical refactoring that groups legacy cgroup v1 fields within struct mem_cgroup into a separate struct mem_cgroup_v1 (accessed via memcg-\u003ev1.\u003cfield\u003e). \n\n1. Allocation \u0026 Initialization: The parent structure struct mem_cgroup continues to be allocated using kmem_cache_zalloc() in mem_cgroup_alloc(), ensuring all embedded members, including struct mem_cgroup_v1, are completely zero-initialized. Mutexes, list heads, spinlocks, and page counters are initialized exactly as before in mem_cgroup_css_alloc() and memcg1_memcg_init().\n2. Data Flow \u0026 Leak Potential: No kernel memory is copied to user space, no new stack/heap allocations are introduced without zeroing, and no data bounds, lengths, or control flow logic are modified.\n3. KASAN vs KMSAN: KMSAN is designed to detect uninitialized memory reads and information leaks. This patch introduces no uninitialized memory risks. Any structural or pointer issues resulting from refactoring would be caught by standard build checks, KASAN, or LOCKDEP. Thus, a dedicated KMSAN run is not justified.", "NeedsKMSAN": false, "Reasoning": "The patch refactors the legacy cgroup v1 memory controller state by grouping its fields from struct mem_cgroup into a dedicated struct mem_cgroup_v1, updating all access sites across mm/memcontrol-v1.c, mm/memcontrol.c, and networking headers. This modifies reachable core memory management and cgroup logic, making it relevant for fuzzing to detect any latent regressions or semantic inconsistencies.", "WorthFuzzing": true }
1/1	2026/09/18 03:16	action	read-patch-diff	0m Args: null Results: { "PatchDiff": "commit 3493b33849dba823c6e0d5716f3a96b262323a35\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Fri Sep 18 03:16:30 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst\nindex 7d2a44af52c93..2eff1dc6e13b2 100644\n--- a/Documentation/admin-guide/cgroup-v1/memory.rst\n+++ b/Documentation/admin-guide/cgroup-v1/memory.rst\n@@ -8,6 +8,13 @@ Memory Resource Controller\n here but make sure to check the current code if you need a deeper\n understanding.\n \n+.. note::\n+ The legacy (v1) memory controller implementation is isolated behind\n+ ``CONFIG_MEMCG_V1``: its interface lives in ``mm/memcontrol-v1.c`` and\n+ its per-cgroup state in ``struct mem_cgroup_v1`` (see\n+ ``include/linux/memcontrol.h``). New functionality belongs to the\n+ cgroup v2 memory controller.\n+\n .. note::\n The Memory Resource Controller has generically been referred to as the\n memory controller in this document. Do not confuse memory controller\ndiff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h\nindex 64c183be8cbfe..4d0d99b57ce99 100644\n--- a/include/linux/memcontrol.h\n+++ b/include/linux/memcontrol.h\n@@ -193,6 +193,43 @@ struct obj_cgroup {\n * statistics based on the statistics developed by Rik Van Riel for clock-pro,\n * to help the administrator determine what knobs to tune.\n /\n+/\n+ * Legacy cgroup v1 memory controller state, used only by the v1\n+ * interface (mm/memcontrol-v1.c).\n+ /\n+struct mem_cgroup_v1 {\n+\tstruct page_counter kmem;\n+\tstruct page_counter tcpmem;\n+\n+\tstruct memcg1_events_percpu __percpu events_percpu;\n+\n+\t/* protected by memcg_oom_lock /\n+\tbool oom_lock;\n+\tint under_oom;\n+\n+\tint oom_kill_disable;\n+\n+\tstruct mutex thresholds_lock;\n+\n+\t/ RCU-protected /\n+\tstruct mem_cgroup_thresholds thresholds;\n+\n+\t/ RCU-protected /\n+\tstruct mem_cgroup_thresholds memsw_thresholds;\n+\n+\t/ For oom notifier event fd /\n+\tstruct list_head oom_notify;\n+\n+\tbool tcpmem_active;\n+\tint tcpmem_pressure;\n+\n+\t/ List of events which userspace want to receive /\n+\tstruct list_head event_list;\n+\tspinlock_t event_list_lock;\n+\n+\tint swappiness;\n+};\n+\n struct mem_cgroup {\n \tstruct cgroup_subsys_state css;\n \n@@ -271,42 +308,7 @@ struct mem_cgroup {\n \t__cacheline_group_end_aligned(memcg_cold);\n \n #ifdef CONFIG_MEMCG_V1\n-\t/ v1 only. Not grouped: v1 is legacy, sorting it is not worth it. /\n-\n-\t/ Legacy consumer-oriented counters /\n-\tstruct page_counter kmem;\t\t/ v1 only /\n-\tstruct page_counter tcpmem;\t\t/ v1 only /\n-\n-\tstruct memcg1_events_percpu __percpu events_percpu;\n-\n-\t/* protected by memcg_oom_lock /\n-\tbool oom_lock;\n-\tint under_oom;\n-\n-\t/ OOM-Killer disable /\n-\tint oom_kill_disable;\n-\n-\t/ protect arrays of thresholds /\n-\tstruct mutex thresholds_lock;\n-\n-\t/ thresholds for memory usage. RCU-protected /\n-\tstruct mem_cgroup_thresholds thresholds;\n-\n-\t/ thresholds for mem+swap usage. RCU-protected /\n-\tstruct mem_cgroup_thresholds memsw_thresholds;\n-\n-\t/ For oom notifier event fd /\n-\tstruct list_head oom_notify;\n-\n-\t/ Legacy tcp memory accounting /\n-\tbool tcpmem_active;\n-\tint tcpmem_pressure;\n-\n-\t/ List of events which userspace want to receive /\n-\tstruct list_head event_list;\n-\tspinlock_t event_list_lock;\n-\n-\tint swappiness;\n+\tstruct mem_cgroup_v1 v1;\n #endif / CONFIG_MEMCG_V1 /\n \n \t/\ndiff --git a/include/net/sock.h b/include/net/sock.h\nindex 51185222aac29..00e0a3f6a2e97 100644\n--- a/include/net/sock.h\n+++ b/include/net/sock.h\n@@ -2705,7 +2705,7 @@ static inline bool mem_cgroup_sk_under_memory_pressure(const struct sock sk)\n \n #ifdef CONFIG_MEMCG_V1\n \tif (!cgroup_subsys_on_dfl(memory_cgrp_subsys))\n-\t\treturn !!memcg-\u003etcpmem_pressure;\n+\t\treturn !!memcg-\u003ev1.tcpmem_pressure;\n #endif / CONFIG_MEMCG_V1 /\n \n \tdo {\ndiff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c\nindex bf2c7d53b01b1..486df2d6a6f17 100644\n--- a/mm/memcontrol-v1.c\n+++ b/mm/memcontrol-v1.c\n@@ -138,9 +138,9 @@ static void __mem_cgroup_threshold(struct mem_cgroup memcg, bool swap)\n \n \trcu_read_lock();\n \tif (!swap)\n-\t\tt = rcu_dereference(memcg-\u003ethresholds.primary);\n+\t\tt = rcu_dereference(memcg-\u003ev1.thresholds.primary);\n \telse\n-\t\tt = rcu_dereference(memcg-\u003ememsw_thresholds.primary);\n+\t\tt = rcu_dereference(memcg-\u003ev1.memsw_thresholds.primary);\n \n \tif (!t)\n \t\tgoto unlock;\n@@ -215,7 +215,7 @@ static void memcg1_charge_statistics(struct mem_cgroup memcg, int nr_pages)\n \t\tnr_pages = -nr_pages; / for event /\n \t}\n \n-\t__this_cpu_add(memcg-\u003eevents_percpu-\u003enr_page_events, nr_pages);\n+\t__this_cpu_add(memcg-\u003ev1.events_percpu-\u003enr_page_events, nr_pages);\n }\n \n #define THRESHOLDS_EVENTS_TARGET 128\n@@ -224,11 +224,11 @@ static bool memcg1_event_ratelimit(struct mem_cgroup memcg)\n {\n \tunsigned long val, next;\n \n-\tval = __this_cpu_read(memcg-\u003eevents_percpu-\u003enr_page_events);\n-\tnext = __this_cpu_read(memcg-\u003eevents_percpu-\u003ethreshold_target);\n+\tval = __this_cpu_read(memcg-\u003ev1.events_percpu-\u003enr_page_events);\n+\tnext = __this_cpu_read(memcg-\u003ev1.events_percpu-\u003ethreshold_target);\n \t/* from time_after() in jiffies.h /\n \tif ((long)(next - val) \u003c 0) {\n-\t\t__this_cpu_write(memcg-\u003eevents_percpu-\u003ethreshold_target,\n+\t\t__this_cpu_write(memcg-\u003ev1.events_percpu-\u003ethreshold_target,\n \t\t\t\t val + THRESHOLDS_EVENTS_TARGET);\n \t\treturn true;\n \t}\n@@ -383,7 +383,7 @@ void memcg1_uncharge_batch(struct mem_cgroup memcg, unsigned long pgpgout,\n \n \tlocal_irq_save(flags);\n \tcount_memcg_events(memcg, PGPGOUT, pgpgout);\n-\t__this_cpu_add(memcg-\u003eevents_percpu-\u003enr_page_events, nr_memory);\n+\t__this_cpu_add(memcg-\u003ev1.events_percpu-\u003enr_page_events, nr_memory);\n \tmemcg1_check_events(memcg);\n \tlocal_irq_restore(flags);\n }\n@@ -408,7 +408,7 @@ static void mem_cgroup_oom_notify_cb(struct mem_cgroup memcg)\n \n \tspin_lock(\u0026memcg_oom_lock);\n \n-\tlist_for_each_entry(ev, \u0026memcg-\u003eoom_notify, list)\n+\tlist_for_each_entry(ev, \u0026memcg-\u003ev1.oom_notify, list)\n \t\teventfd_signal(ev-\u003eeventfd);\n \n \tspin_unlock(\u0026memcg_oom_lock);\n@@ -435,13 +435,13 @@ static int __mem_cgroup_usage_register_event(struct mem_cgroup memcg,\n \tif (ret)\n \t\treturn ret;\n \n-\tmutex_lock(\u0026memcg-\u003ethresholds_lock);\n+\tmutex_lock(\u0026memcg-\u003ev1.thresholds_lock);\n \n \tif (type == _MEM) {\n-\t\tthresholds = \u0026memcg-\u003ethresholds;\n+\t\tthresholds = \u0026memcg-\u003ev1.thresholds;\n \t\tusage = mem_cgroup_usage(memcg, false);\n \t} else if (type == _MEMSWAP) {\n-\t\tthresholds = \u0026memcg-\u003ememsw_thresholds;\n+\t\tthresholds = \u0026memcg-\u003ev1.memsw_thresholds;\n \t\tusage = mem_cgroup_usage(memcg, true);\n \t} else\n \t\tBUG();\n@@ -497,7 +497,7 @@ static int __mem_cgroup_usage_register_event(struct mem_cgroup memcg,\n \tsynchronize_rcu();\n \n unlock:\n-\tmutex_unlock(\u0026memcg-\u003ethresholds_lock);\n+\tmutex_unlock(\u0026memcg-\u003ev1.thresholds_lock);\n \n \treturn ret;\n }\n@@ -522,13 +522,13 @@ static void __mem_cgroup_usage_unregister_event(struct mem_cgroup memcg,\n \tunsigned long usage;\n \tint i, j, size, entries;\n \n-\tmutex_lock(\u0026memcg-\u003ethresholds_lock);\n+\tmutex_lock(\u0026memcg-\u003ev1.thresholds_lock);\n \n \tif (type == _MEM) {\n-\t\tthresholds = \u0026memcg-\u003ethresholds;\n+\t\tthresholds = \u0026memcg-\u003ev1.thresholds;\n \t\tusage = mem_cgroup_usage(memcg, false);\n \t} else if (type == _MEMSWAP) {\n-\t\tthresholds = \u0026memcg-\u003ememsw_thresholds;\n+\t\tthresholds = \u0026memcg-\u003ev1.memsw_thresholds;\n \t\tusage = mem_cgroup_usage(memcg, true);\n \t} else\n \t\tBUG();\n@@ -596,7 +596,7 @@ static void __mem_cgroup_usage_unregister_event(struct mem_cgroup memcg,\n \t\tthresholds-\u003espare = NULL;\n \t}\n unlock:\n-\tmutex_unlock(\u0026memcg-\u003ethresholds_lock);\n+\tmutex_unlock(\u0026memcg-\u003ev1.thresholds_lock);\n }\n \n static void mem_cgroup_usage_unregister_event(struct mem_cgroup memcg,\n@@ -623,10 +623,10 @@ static int mem_cgroup_oom_register_event(struct mem_cgroup memcg,\n \tspin_lock(\u0026memcg_oom_lock);\n \n \tevent-\u003eeventfd = eventfd;\n-\tlist_add(\u0026event-\u003elist, \u0026memcg-\u003eoom_notify);\n+\tlist_add(\u0026event-\u003elist, \u0026memcg-\u003ev1.oom_notify);\n \n \t/ already in OOM ? /\n-\tif (memcg-\u003eunder_oom)\n+\tif (memcg-\u003ev1.under_oom)\n \t\teventfd_signal(eventfd);\n \tspin_unlock(\u0026memcg_oom_lock);\n \n@@ -640,7 +640,7 @@ static void mem_cgroup_oom_unregister_event(struct mem_cgroup memcg,\n \n \tspin_lock(\u0026memcg_oom_lock);\n \n-\tlist_for_each_entry_safe(ev, tmp, \u0026memcg-\u003eoom_notify, list) {\n+\tlist_for_each_entry_safe(ev, tmp, \u0026memcg-\u003ev1.oom_notify, list) {\n \t\tif (ev-\u003eeventfd == eventfd) {\n \t\t\tlist_del(\u0026ev-\u003elist);\n \t\t\tkfree(ev);\n@@ -709,7 +709,7 @@ static int memcg_event_wake(wait_queue_entry_t wait, unsigned int mode,\n \t\t side will require wqh-\u003elock via remove_wait_queue(),\n \t\t * which we hold.\n \t\t /\n-\t\tspin_lock(\u0026memcg-\u003eevent_list_lock);\n+\t\tspin_lock(\u0026memcg-\u003ev1.event_list_lock);\n \t\tif (!list_empty(\u0026event-\u003elist)) {\n \t\t\tlist_del_init(\u0026event-\u003elist);\n \t\t\t/\n@@ -718,7 +718,7 @@ static int memcg_event_wake(wait_queue_entry_t wait, unsigned int mode,\n \t\t\t /\n \t\t\tschedule_work(\u0026event-\u003eremove);\n \t\t}\n-\t\tspin_unlock(\u0026memcg-\u003eevent_list_lock);\n+\t\tspin_unlock(\u0026memcg-\u003ev1.event_list_lock);\n \t}\n \n \treturn 0;\n@@ -868,9 +868,9 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file of,\n \n \tvfs_poll(fd_file(efile), \u0026event-\u003ept);\n \n-\tspin_lock_irq(\u0026memcg-\u003eevent_list_lock);\n-\tlist_add(\u0026event-\u003elist, \u0026memcg-\u003eevent_list);\n-\tspin_unlock_irq(\u0026memcg-\u003eevent_list_lock);\n+\tspin_lock_irq(\u0026memcg-\u003ev1.event_list_lock);\n+\tlist_add(\u0026event-\u003elist, \u0026memcg-\u003ev1.event_list);\n+\tspin_unlock_irq(\u0026memcg-\u003ev1.event_list_lock);\n \treturn nbytes;\n \n out_put_css:\n@@ -884,10 +884,10 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file of,\n \n void memcg1_memcg_init(struct mem_cgroup memcg)\n {\n-\tINIT_LIST_HEAD(\u0026memcg-\u003eoom_notify);\n-\tmutex_init(\u0026memcg-\u003ethresholds_lock);\n-\tINIT_LIST_HEAD(\u0026memcg-\u003eevent_list);\n-\tspin_lock_init(\u0026memcg-\u003eevent_list_lock);\n+\tINIT_LIST_HEAD(\u0026memcg-\u003ev1.oom_notify);\n+\tmutex_init(\u0026memcg-\u003ev1.thresholds_lock);\n+\tINIT_LIST_HEAD(\u0026memcg-\u003ev1.event_list);\n+\tspin_lock_init(\u0026memcg-\u003ev1.event_list_lock);\n }\n \n void memcg1_css_offline(struct mem_cgroup memcg)\n@@ -899,12 +899,12 @@ void memcg1_css_offline(struct mem_cgroup memcg)\n \t Notify userspace about cgroup removing only after rmdir of cgroup\n \t * directory to avoid race between userspace and kernelspace.\n \t /\n-\tspin_lock_irq(\u0026memcg-\u003eevent_list_lock);\n-\tlist_for_each_entry_safe(event, tmp, \u0026memcg-\u003eevent_list, list) {\n+\tspin_lock_irq(\u0026memcg-\u003ev1.event_list_lock);\n+\tlist_for_each_entry_safe(event, tmp, \u0026memcg-\u003ev1.event_list, list) {\n \t\tlist_del_init(\u0026event-\u003elist);\n \t\tschedule_work(\u0026event-\u003eremove);\n \t}\n-\tspin_unlock_irq(\u0026memcg-\u003eevent_list_lock);\n+\tspin_unlock_irq(\u0026memcg-\u003ev1.event_list_lock);\n }\n \n /\n@@ -918,7 +918,7 @@ static bool mem_cgroup_oom_trylock(struct mem_cgroup memcg)\n \tspin_lock(\u0026memcg_oom_lock);\n \n \tfor_each_mem_cgroup_tree(iter, memcg) {\n-\t\tif (iter-\u003eoom_lock) {\n+\t\tif (iter-\u003ev1.oom_lock) {\n \t\t\t/\n \t\t\t * this subtree of our hierarchy is already locked\n \t\t\t * so we cannot give a lock.\n@@ -927,7 +927,7 @@ static bool mem_cgroup_oom_trylock(struct mem_cgroup memcg)\n \t\t\tmem_cgroup_iter_break(memcg, iter);\n \t\t\tbreak;\n \t\t}\n-\t\titer-\u003eoom_lock = true;\n+\t\titer-\u003ev1.oom_lock = true;\n \t}\n \n \tif (failed) {\n@@ -940,7 +940,7 @@ static bool mem_cgroup_oom_trylock(struct mem_cgroup memcg)\n \t\t\t\tmem_cgroup_iter_break(memcg, iter);\n \t\t\t\tbreak;\n \t\t\t}\n-\t\t\titer-\u003eoom_lock = false;\n+\t\t\titer-\u003ev1.oom_lock = false;\n \t\t}\n \t} else\n \t\tmutex_acquire(\u0026memcg_oom_lock_dep_map, 0, 1, _RET_IP_);\n@@ -957,7 +957,7 @@ static void mem_cgroup_oom_unlock(struct mem_cgroup memcg)\n \tspin_lock(\u0026memcg_oom_lock);\n \tmutex_release(\u0026memcg_oom_lock_dep_map, _RET_IP_);\n \tfor_each_mem_cgroup_tree(iter, memcg)\n-\t\titer-\u003eoom_lock = false;\n+\t\titer-\u003ev1.oom_lock = false;\n \tspin_unlock(\u0026memcg_oom_lock);\n }\n \n@@ -967,7 +967,7 @@ static void mem_cgroup_mark_under_oom(struct mem_cgroup memcg)\n \n \tspin_lock(\u0026memcg_oom_lock);\n \tfor_each_mem_cgroup_tree(iter, memcg)\n-\t\titer-\u003eunder_oom++;\n+\t\titer-\u003ev1.under_oom++;\n \tspin_unlock(\u0026memcg_oom_lock);\n }\n \n@@ -981,8 +981,8 @@ static void mem_cgroup_unmark_under_oom(struct mem_cgroup memcg)\n \t /\n \tspin_lock(\u0026memcg_oom_lock);\n \tfor_each_mem_cgroup_tree(iter, memcg)\n-\t\tif (iter-\u003eunder_oom \u003e 0)\n-\t\t\titer-\u003eunder_oom--;\n+\t\tif (iter-\u003ev1.under_oom \u003e 0)\n+\t\t\titer-\u003ev1.under_oom--;\n \tspin_unlock(\u0026memcg_oom_lock);\n }\n \n@@ -1012,14 +1012,14 @@ static int memcg_oom_wake_function(wait_queue_entry_t wait,\n void memcg1_oom_recover(struct mem_cgroup memcg)\n {\n \t/\n-\t For the following lockless -\u003eunder_oom test, the only required\n+\t * For the following lockless -\u003ev1.under_oom test, the only required\n \t * guarantee is that it must see the state asserted by an OOM when\n \t * this function is called as a result of userland actions\n \t * triggered by the notification of the OOM. This is trivially\n \t * achieved by invoking mem_cgroup_mark_under_oom() before\n \t * triggering notification.\n \t /\n-\tif (memcg \u0026\u0026 memcg-\u003eunder_oom)\n+\tif (memcg \u0026\u0026 memcg-\u003ev1.under_oom)\n \t\t__wake_up(\u0026memcg_oom_waitq, TASK_NORMAL, 0, memcg);\n }\n \n@@ -1100,7 +1100,7 @@ bool memcg1_oom_prepare(struct mem_cgroup memcg, bool locked)\n \t Please note that mem_cgroup_out_of_memory might fail to find a\n \t * victim and then we have to bail out from the charge path.\n \t /\n-\tif (READ_ONCE(memcg-\u003eoom_kill_disable)) {\n+\tif (READ_ONCE(memcg-\u003ev1.oom_kill_disable)) {\n \t\tif (current-\u003ein_user_fault) {\n \t\t\tcss_get(\u0026memcg-\u003ecss);\n \t\t\tcurrent-\u003ememcg_in_oom = memcg;\n@@ -1576,10 +1576,10 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state css,\n \t\tcounter = \u0026memcg-\u003ememsw;\n \t\tbreak;\n \tcase _KMEM:\n-\t\tcounter = \u0026memcg-\u003ekmem;\n+\t\tcounter = \u0026memcg-\u003ev1.kmem;\n \t\tbreak;\n \tcase _TCP:\n-\t\tcounter = \u0026memcg-\u003etcpmem;\n+\t\tcounter = \u0026memcg-\u003ev1.tcpmem;\n \t\tbreak;\n \tdefault:\n \t\tBUG();\n@@ -1619,11 +1619,11 @@ static int memcg_update_tcp_max(struct mem_cgroup memcg, unsigned long max)\n \n \tmutex_lock(\u0026memcg_max_mutex);\n \n-\tret = page_counter_set_max(\u0026memcg-\u003etcpmem, max);\n+\tret = page_counter_set_max(\u0026memcg-\u003ev1.tcpmem, max);\n \tif (ret)\n \t\tgoto out;\n \n-\tif (!memcg-\u003etcpmem_active) {\n+\tif (!memcg-\u003ev1.tcpmem_active) {\n \t\t/\n \t\t * The active flag needs to be written after the static_key\n \t\t * update. This is what guarantees that the socket activation\n@@ -1641,7 +1641,7 @@ static int memcg_update_tcp_max(struct mem_cgroup memcg, unsigned long max)\n \t\t patched in yet.\n \t\t /\n \t\tstatic_branch_inc(\u0026memcg_sockets_enabled_key);\n-\t\tmemcg-\u003etcpmem_active = true;\n+\t\tmemcg-\u003ev1.tcpmem_active = true;\n \t}\n out:\n \tmutex_unlock(\u0026memcg_max_mutex);\n@@ -1710,10 +1710,10 @@ static ssize_t mem_cgroup_reset(struct kernfs_open_file of, char buf,\n \t\tcounter = \u0026memcg-\u003ememsw;\n \t\tbreak;\n \tcase _KMEM:\n-\t\tcounter = \u0026memcg-\u003ekmem;\n+\t\tcounter = \u0026memcg-\u003ev1.kmem;\n \t\tbreak;\n \tcase _TCP:\n-\t\tcounter = \u0026memcg-\u003etcpmem;\n+\t\tcounter = \u0026memcg-\u003ev1.tcpmem;\n \t\tbreak;\n \tdefault:\n \t\tBUG();\n@@ -1976,7 +1976,7 @@ static int mem_cgroup_swappiness_write(struct cgroup_subsys_state css,\n \tif (!mem_cgroup_is_root(memcg)) {\n \t\tpr_info_once(\"Per memcg swappiness does not exist in cgroup v2. \"\n \t\t\t \"See memory.reclaim or memory.swap.max there\\n \");\n-\t\tWRITE_ONCE(memcg-\u003eswappiness, val);\n+\t\tWRITE_ONCE(memcg-\u003ev1.swappiness, val);\n \t} else\n \t\tWRITE_ONCE(vm_swappiness, val);\n \n@@ -1987,8 +1987,8 @@ static int mem_cgroup_oom_control_read(struct seq_file sf, void v)\n {\n \tstruct mem_cgroup memcg = mem_cgroup_from_seq(sf);\n \n-\tseq_printf(sf, \"oom_kill_disable %d\\n\", READ_ONCE(memcg-\u003eoom_kill_disable));\n-\tseq_printf(sf, \"under_oom %d\\n\", (bool)memcg-\u003eunder_oom);\n+\tseq_printf(sf, \"oom_kill_disable %d\\n\", READ_ONCE(memcg-\u003ev1.oom_kill_disable));\n+\tseq_printf(sf, \"under_oom %d\\n\", (bool)memcg-\u003ev1.under_oom);\n \tseq_printf(sf, \"oom_kill %lu\\n\",\n \t\t atomic_long_read(\u0026memcg-\u003ememory_events[MEMCG_OOM_KILL]));\n \treturn 0;\n@@ -2007,7 +2007,7 @@ static int mem_cgroup_oom_control_write(struct cgroup_subsys_state css,\n \tif (mem_cgroup_is_root(memcg) \|\| !((val == 0) \|\| (val == 1)))\n \t\treturn -EINVAL;\n \n-\tWRITE_ONCE(memcg-\u003eoom_kill_disable, val);\n+\tWRITE_ONCE(memcg-\u003ev1.oom_kill_disable, val);\n \tif (!val)\n \t\tmemcg1_oom_recover(memcg);\n \n@@ -2183,9 +2183,9 @@ void memcg1_account_kmem(struct mem_cgroup memcg, int nr_pages)\n {\n \tif (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {\n \t\tif (nr_pages \u003e 0)\n-\t\t\tpage_counter_charge(\u0026memcg-\u003ekmem, nr_pages);\n+\t\t\tpage_counter_charge(\u0026memcg-\u003ev1.kmem, nr_pages);\n \t\telse\n-\t\t\tpage_counter_uncharge(\u0026memcg-\u003ekmem, -nr_pages);\n+\t\t\tpage_counter_uncharge(\u0026memcg-\u003ev1.kmem, -nr_pages);\n \t}\n }\n \n@@ -2194,13 +2194,13 @@ bool memcg1_charge_skmem(struct mem_cgroup memcg, unsigned int nr_pages,\n {\n \tstruct page_counter fail;\n \n-\tif (page_counter_try_charge(\u0026memcg-\u003etcpmem, nr_pages, \u0026fail)) {\n-\t\tmemcg-\u003etcpmem_pressure = 0;\n+\tif (page_counter_try_charge(\u0026memcg-\u003ev1.tcpmem, nr_pages, \u0026fail)) {\n+\t\tmemcg-\u003ev1.tcpmem_pressure = 0;\n \t\treturn true;\n \t}\n-\tmemcg-\u003etcpmem_pressure = 1;\n+\tmemcg-\u003ev1.tcpmem_pressure = 1;\n \tif (gfp_mask \u0026 __GFP_NOFAIL) {\n-\t\tpage_counter_charge(\u0026memcg-\u003etcpmem, nr_pages);\n+\t\tpage_counter_charge(\u0026memcg-\u003ev1.tcpmem, nr_pages);\n \t\treturn true;\n \t}\n \treturn false;\n@@ -2208,12 +2208,12 @@ bool memcg1_charge_skmem(struct mem_cgroup memcg, unsigned int nr_pages,\n \n bool memcg1_alloc_events(struct mem_cgroup memcg)\n {\n-\tmemcg-\u003eevents_percpu = alloc_percpu_gfp(struct memcg1_events_percpu,\n+\tmemcg-\u003ev1.events_percpu = alloc_percpu_gfp(struct memcg1_events_percpu,\n \t\t\t\t\t\tGFP_KERNEL_ACCOUNT);\n-\treturn !!memcg-\u003eevents_percpu;\n+\treturn !!memcg-\u003ev1.events_percpu;\n }\n \n void memcg1_free_events(struct mem_cgroup memcg)\n {\n-\tfree_percpu(memcg-\u003eevents_percpu);\n+\tfree_percpu(memcg-\u003ev1.events_percpu);\n }\ndiff --git a/mm/memcontrol-v1.h b/mm/memcontrol-v1.h\nindex 0952b2a783e52..cc41aa22af019 100644\n--- a/mm/memcontrol-v1.h\n+++ b/mm/memcontrol-v1.h\n@@ -74,13 +74,13 @@ void reparent_memcg_state_local(struct mem_cgroup memcg,\n void memcg1_account_kmem(struct mem_cgroup memcg, int nr_pages);\n static inline bool memcg1_tcpmem_active(struct mem_cgroup memcg)\n {\n-\treturn memcg-\u003etcpmem_active;\n+\treturn memcg-\u003ev1.tcpmem_active;\n }\n bool memcg1_charge_skmem(struct mem_cgroup memcg, unsigned int nr_pages,\n \t\t\t gfp_t gfp_mask);\n static inline void memcg1_uncharge_skmem(struct mem_cgroup memcg, unsigned int nr_pages)\n {\n-\tpage_counter_uncharge(\u0026memcg-\u003etcpmem, nr_pages);\n+\tpage_counter_uncharge(\u0026memcg-\u003ev1.tcpmem, nr_pages);\n }\n \n extern struct cftype memsw_files[];\ndiff --git a/mm/memcontrol.c b/mm/memcontrol.c\nindex 4d00748c8a5b8..4c883956d84ab 100644\n--- a/mm/memcontrol.c\n+++ b/mm/memcontrol.c\n@@ -1882,8 +1882,8 @@ void mem_cgroup_print_oom_meminfo(struct mem_cgroup memcg)\n \t\t\tK((u64)page_counter_read(\u0026memcg-\u003ememsw)),\n \t\t\tK((u64)memcg-\u003ememsw.max), memcg-\u003ememsw.failcnt);\n \t\tpr_info(\"kmem: usage %llukB, limit %llukB, failcnt %lu\\n\",\n-\t\t\tK((u64)page_counter_read(\u0026memcg-\u003ekmem)),\n-\t\t\tK((u64)memcg-\u003ekmem.max), memcg-\u003ekmem.failcnt);\n+\t\t\tK((u64)page_counter_read(\u0026memcg-\u003ev1.kmem)),\n+\t\t\tK((u64)memcg-\u003ev1.kmem.max), memcg-\u003ev1.kmem.failcnt);\n \t}\n #endif\n \n@@ -4300,13 +4300,13 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state parent_css)\n \t\tpage_counter_init(\u0026memcg-\u003ememory, \u0026parent-\u003ememory, memcg_on_dfl);\n \t\tpage_counter_init(\u0026memcg-\u003eswap, \u0026parent-\u003eswap, false);\n #ifdef CONFIG_MEMCG_V1\n-\t\tWRITE_ONCE(memcg-\u003eswappiness, mem_cgroup_swappiness(parent));\n+\t\tWRITE_ONCE(memcg-\u003ev1.swappiness, mem_cgroup_swappiness(parent));\n \t\tmemcg-\u003ememory.track_failcnt = !memcg_on_dfl;\n \t\tmemcg-\u003ememsw.track_failcnt = !memcg_on_dfl;\n-\t\tWRITE_ONCE(memcg-\u003eoom_kill_disable, READ_ONCE(parent-\u003eoom_kill_disable));\n-\t\tpage_counter_init(\u0026memcg-\u003ekmem, \u0026parent-\u003ekmem, false);\n-\t\tpage_counter_init(\u0026memcg-\u003etcpmem, \u0026parent-\u003etcpmem, false);\n-\t\tmemcg-\u003etcpmem.track_failcnt = !memcg_on_dfl;\n+\t\tWRITE_ONCE(memcg-\u003ev1.oom_kill_disable, READ_ONCE(parent-\u003ev1.oom_kill_disable));\n+\t\tpage_counter_init(\u0026memcg-\u003ev1.kmem, \u0026parent-\u003ev1.kmem, false);\n+\t\tpage_counter_init(\u0026memcg-\u003ev1.tcpmem, \u0026parent-\u003ev1.tcpmem, false);\n+\t\tmemcg-\u003ev1.tcpmem.track_failcnt = !memcg_on_dfl;\n #endif\n \t} else {\n \t\tinit_memcg_stats();\n@@ -4314,8 +4314,8 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state parent_css)\n \t\tpage_counter_init(\u0026memcg-\u003ememory, NULL, true);\n \t\tpage_counter_init(\u0026memcg-\u003eswap, NULL, false);\n #ifdef CONFIG_MEMCG_V1\n-\t\tpage_counter_init(\u0026memcg-\u003ekmem, NULL, false);\n-\t\tpage_counter_init(\u0026memcg-\u003etcpmem, NULL, false);\n+\t\tpage_counter_init(\u0026memcg-\u003ev1.kmem, NULL, false);\n+\t\tpage_counter_init(\u0026memcg-\u003ev1.tcpmem, NULL, false);\n #endif\n \t\troot_mem_cgroup = memcg;\n \t\treturn \u0026memcg-\u003ecss;\n@@ -4492,8 +4492,8 @@ static void mem_cgroup_css_reset(struct cgroup_subsys_state css)\n \tWRITE_ONCE(memcg-\u003ezswap_writeback, true);\n #endif\n #ifdef CONFIG_MEMCG_V1\n-\tpage_counter_set_max(\u0026memcg-\u003ekmem, PAGE_COUNTER_MAX);\n-\tpage_counter_set_max(\u0026memcg-\u003etcpmem, PAGE_COUNTER_MAX);\n+\tpage_counter_set_max(\u0026memcg-\u003ev1.kmem, PAGE_COUNTER_MAX);\n+\tpage_counter_set_max(\u0026memcg-\u003ev1.tcpmem, PAGE_COUNTER_MAX);\n #endif\n \tpage_counter_set_min(\u0026memcg-\u003ememory, 0);\n \tpage_counter_set_low(\u0026memcg-\u003ememory, 0);\ndiff --git a/mm/swap.h b/mm/swap.h\nindex d5bf21f517dce..dc54f9a123567 100644\n--- a/mm/swap.h\n+++ b/mm/swap.h\n@@ -87,7 +87,7 @@ static inline int mem_cgroup_swappiness(const struct mem_cgroup memcg)\n #ifdef CONFIG_MEMCG_V1\n \tif (!cgroup_subsys_on_dfl(memory_cgrp_subsys) \u0026\u0026\n \t !mem_cgroup_disabled() \u0026\u0026 !mem_cgroup_is_root(memcg))\n-\t\treturn READ_ONCE(memcg-\u003eswappiness);\n+\t\treturn READ_ONCE(memcg-\u003ev1.swappiness);\n #endif\n \treturn READ_ONCE(vm_swappiness);\n }\n" }
2/1	2026/09/18 03:16	agent	patch-evaluator	1m Model: core Args: null Results: { "EnableConfigs": [ "CGROUPS", "MEMCG", "MEMCG_V1" ], "FocusSymbols": [ "memcg_write_event_control", "memcg_update_tcp_max", "mem_cgroup_swappiness_write", "mem_cgroup_oom_control_write", "mem_cgroup_oom_register_event", "__mem_cgroup_usage_register_event", "memcg1_oom_recover" ], "Reasoning": "The patch refactors the legacy cgroup v1 memory controller state by grouping its fields from struct mem_cgroup into a dedicated struct mem_cgroup_v1, updating all access sites across mm/memcontrol-v1.c, mm/memcontrol.c, and networking headers. This modifies reachable core memory management and cgroup logic, making it relevant for fuzzing to detect any latent regressions or semantic inconsistencies.", "WorthFuzzing": true } Instruction: You are an expert Linux kernel maintainer and security engineer. Your job is to review a provided patch series and evaluate whether it warrants fuzzing with syzkaller. IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in your workspace. Do NOT rely on internal assumptions. You must actively use your code access tools to inspect the actual source code, callers, and surrounding context. ================================================================================ 1. CORE TRIAGE PHILOSOPHY ================================================================================ The goal of patch fuzzing is to discover crashes, regressions, exposed latent bugs, and newly triggered assertions introduced by the patch series. - REACHABILITY IS THE PRIMARY GATE: Fuzzing can only discover bugs in code that can actually execute in standard virtualized environments (GCE or QEMU, utilizing software-emulated devices like USB gadgets, netdev, tun/tap). If the modified code is structurally unreachable (see Section 2), it MUST NOT be fuzzed, regardless of whether it adds assertions or complex logic. - DO NOT BLINDLY TRUST "NO FUNCTIONAL CHANGE" (NFCI) OR "REFACTORING" CLAIMS: Patch authors routinely label changes as "cleanups", "refactorings", or state "No functional change intended". Do NOT take these claims at face value. Code refactorings that rearrange logic, introduce helper functions, or alter state management in core subsystems frequently introduce subtle semantic shifts or uncover latent kernel bugs. If reachable executable code is modified or refactored, it MUST be fuzzed. - NEW OR MODIFIED ASSERTIONS IN REACHABLE CODE MUST BE FUZZED: When a patch introduces or modifies runtime checks or assertions (e.g., WARN_ON, VM_WARN_ON, BUG_ON, lockdep_assert) in reachable code paths, it enforces new or stricter invariants. Even if the author believes the invariant always holds, fuzzing is essential to verify whether an unusual sequence of operations can violate it. ================================================================================ 2. WHEN TO RETURN WorthFuzzing=false (NEGATIVE CRITERIA) ================================================================================ Return WorthFuzzing=false ONLY IF all modified code falls strictly into one or more of these categories: - Non-kernel and non-executable changes: * Modifications to Documentation/, comments, or spelling fixes. * User-space directories, self-tests, samples, or scripts (e.g., tools/, samples/, scripts/, usr/) that do not affect the compiled kernel image (vmlinux) or kernel modules. * Purely decorative logging (e.g., message strings in pr_err, printk, dev_info) or tracepoints that do not alter control flow or data structures. * Build system or Kconfig changes that do not alter compiled C logic. - Structurally unreachable hardware: * Vendor-specific PCIe switches, SmartNICs, or GPU drivers (e.g., mlxsw, pds_core, qed, ionic, amdgpu) requiring physical ASIC/PCIe cards not emulated in standard QEMU. - Unreachable execution paths: * Driver teardown callbacks (.remove, .shutdown, pci_unregister_driver) executed only during physical PCI hot-unplug or manual sysfs driver unbinding. * Code paths exclusive to architectures other than the target architecture. ================================================================================ 3. WHEN TO RETURN WorthFuzzing=true (POSITIVE CRITERIA) ================================================================================ Return WorthFuzzing=true whenever the patch touches reachable executable code, including: - Core Subsystems: * Any logic modifications in memory management (mm/), synchronization/locking (kernel/locking/), BPF, scheduler, core networking, VFS, or syscall handling. - Refactorings and Code Cleanups: * Any restructuring of reachable data structures, helper abstractions, or algorithm flows. - Runtime Assertions and Defensive Checks: * Any introduction or alteration of assertions (WARN_ON, VM_WARN_ON, BUG_ON, etc.) in reachable paths. - Reachable Drivers and Protocols: Drivers accessible via virtual buses (virtio, USB gadget, loopback, netlink, binder, sockets, etc.). ================================================================================ 4. EXTRACTING FocusSymbols (PREVENTING DILUTION) ================================================================================ When WorthFuzzing=true, you must extract specific kernel functions into FocusSymbols to guide the fuzzer: - AVOID UBIQUITOUS LIFECYCLE HOT-PATHS: Do NOT list generic, ubiquitous functions called by almost every program in the corpus (including, but not limited to: general memory allocators and deallocators, page fault and trap handlers, or core synchronization primitives; this is not an exhaustive list). Listing ubiquitous functions causes the fuzzer to classify thousands of unrelated tests as "focused", which severely dilutes fuzzing effort away from the actual changes. - TARGET SPECIFIC FEATURE LOGIC AND ENTRYPOINTS: List functions that specifically implement the logic being added or altered, or direct API entrypoints for the subsystem feature under review. - HANDLING STATIC INLINE FUNCTIONS IN HEADERS (.h): Compiler-inlined static functions (such as static inlines in mm/.h or include/linux/.h) lack distinct symbol addresses in vmlinux and cannot be targeted directly by symbol coverage filters. If the changes are primarily in static inline helpers, identify non-static, feature-specific caller functions in .c files that exercise them (avoiding ubiquitous lifecycle wrappers). ================================================================================ 5. IDENTIFYING EnableConfigs ================================================================================ Identify any specific CONFIG_ options required to properly compile and reach the modified code: - Inspect Kconfig files and #ifdef guards; do not make assumptions. - Check "depends on" lines in Kconfig to include any non-standard parent subsystem configs needed. - Strip any 'CONFIG_' prefix (e.g., return "NET_IPV4" instead of "CONFIG_NET_IPV4"). Prefer calling several tools at the same time to save round-trips. Use set-results tool to provide results of the analysis. It must be called exactly once before the final reply. Ignore results of this tool. Prompt: Target architecture: amd64 For your convenience, here is the diff of the changes: commit 3493b33849dba823c6e0d5716f3a96b262323a35 Author: syz-cluster <triage@syzkaller.com> Date: Fri Sep 18 03:16:30 2026 +0000 syz-cluster: applied patch under review diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst index 7d2a44af52c93..2eff1dc6e13b2 100644 --- a/Documentation/admin-guide/cgroup-v1/memory.rst +++ b/Documentation/admin-guide/cgroup-v1/memory.rst @@ -8,6 +8,13 @@ Memory Resource Controller here but make sure to check the current code if you need a deeper understanding. +.. note:: + The legacy (v1) memory controller implementation is isolated behind + ``CONFIG_MEMCG_V1``: its interface lives in ``mm/memcontrol-v1.c`` and + its per-cgroup state in ``struct mem_cgroup_v1`` (see + ``include/linux/memcontrol.h``). New functionality belongs to the + cgroup v2 memory controller. + .. note:: The Memory Resource Controller has generically been referred to as the memory controller in this document. Do not confuse memory controller diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 64c183be8cbfe..4d0d99b57ce99 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -193,6 +193,43 @@ struct obj_cgroup { * statistics based on the statistics developed by Rik Van Riel for clock-pro, * to help the administrator determine what knobs to tune. / +/ + * Legacy cgroup v1 memory controller state, used only by the v1 + * interface (mm/memcontrol-v1.c). + / +struct mem_cgroup_v1 { + struct page_counter kmem; + struct page_counter tcpmem; + + struct memcg1_events_percpu __percpu events_percpu; + + /* protected by memcg_oom_lock / + bool oom_lock; + int under_oom; + + int oom_kill_disable; + + struct mutex thresholds_lock; + + / RCU-protected / + struct mem_cgroup_thresholds thresholds; + + / RCU-protected / + struct mem_cgroup_thresholds memsw_thresholds; + + / For oom notifier event fd / + struct list_head oom_notify; + + bool tcpmem_active; + int tcpmem_pressure; + + / List of events which userspace want to receive / + struct list_head event_list; + spinlock_t event_list_lock; + + int swappiness; +}; + struct mem_cgroup { struct cgroup_subsys_state css; @@ -271,42 +308,7 @@ struct mem_cgroup { __cacheline_group_end_aligned(memcg_cold); #ifdef CONFIG_MEMCG_V1 - / v1 only. Not grouped: v1 is legacy, sorting it is not worth it. / - - / Legacy consumer-oriented counters / - struct page_counter kmem; / v1 only / - struct page_counter tcpmem; / v1 only / - - struct memcg1_events_percpu __percpu events_percpu; - - /* protected by memcg_oom_lock / - bool oom_lock; - int under_oom; - - / OOM-Killer disable / - int oom_kill_disable; - - / protect arrays of thresholds / - struct mutex thresholds_lock; - - / thresholds for memory usage. RCU-protected / - struct mem_cgroup_thresholds thresholds; - - / thresholds for mem+swap usage. RCU-protected / - struct mem_cgroup_thresholds memsw_thresholds; - - / For oom notifier event fd / - struct list_head oom_notify; - - / Legacy tcp memory accounting / - bool tcpmem_active; - int tcpmem_pressure; - - / List of events which userspace want to receive / - struct list_head event_list; - spinlock_t event_list_lock; - - int swappiness; + struct mem_cgroup_v1 v1; #endif / CONFIG_MEMCG_V1 / / diff --git a/include/net/sock.h b/include/net/sock.h index 51185222aac29..00e0a3f6a2e97 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -2705,7 +2705,7 @@ static inline bool mem_cgroup_sk_under_memory_pressure(const struct sock sk) #ifdef CONFIG_MEMCG_V1 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) - return !!memcg->tcpmem_pressure; + return !!memcg->v1.tcpmem_pressure; #endif / CONFIG_MEMCG_V1 / do { diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c index bf2c7d53b01b1..486df2d6a6f17 100644 --- a/mm/memcontrol-v1.c +++ b/mm/memcontrol-v1.c @@ -138,9 +138,9 @@ static void __mem_cgroup_threshold(struct mem_cgroup memcg, bool swap) rcu_read_lock(); if (!swap) - t = rcu_dereference(memcg->thresholds.primary); + t = rcu_dereference(memcg->v1.thresholds.primary); else - t = rcu_dereference(memcg->memsw_thresholds.primary); + t = rcu_dereference(memcg->v1.memsw_thresholds.primary); if (!t) goto unlock; @@ -215,7 +215,7 @@ static void memcg1_charge_statistics(struct mem_cgroup memcg, int nr_pages) nr_pages = -nr_pages; / for event / } - __this_cpu_add(memcg->events_percpu->nr_page_events, nr_pages); + __this_cpu_add(memcg->v1.events_percpu->nr_page_events, nr_pages); } #define THRESHOLDS_EVENTS_TARGET 128 @@ -224,11 +224,11 @@ static bool memcg1_event_ratelimit(struct mem_cgroup memcg) { unsigned long val, next; - val = __this_cpu_read(memcg->events_percpu->nr_page_events); - next = __this_cpu_read(memcg->events_percpu->threshold_target); + val = __this_cpu_read(memcg->v1.events_percpu->nr_page_events); + next = __this_cpu_read(memcg->v1.events_percpu->threshold_target); /* from time_after() in jiffies.h / if ((long)(next - val) < 0) { - __this_cpu_write(memcg->events_percpu->threshold_target, + __this_cpu_write(memcg->v1.events_percpu->threshold_target, val + THRESHOLDS_EVENTS_TARGET); return true; } @@ -383,7 +383,7 @@ void memcg1_uncharge_batch(struct mem_cgroup memcg, unsigned long pgpgout, local_irq_save(flags); count_memcg_events(memcg, PGPGOUT, pgpgout); - __this_cpu_add(memcg->events_percpu->nr_page_events, nr_memory); + __this_cpu_add(memcg->v1.events_percpu->nr_page_events, nr_memory); memcg1_check_events(memcg); local_irq_restore(flags); } @@ -408,7 +408,7 @@ static void mem_cgroup_oom_notify_cb(struct mem_cgroup memcg) spin_lock(&memcg_oom_lock); - list_for_each_entry(ev, &memcg->oom_notify, list) + list_for_each_entry(ev, &memcg->v1.oom_notify, list) eventfd_signal(ev->eventfd); spin_unlock(&memcg_oom_lock); @@ -435,13 +435,13 @@ static int __mem_cgroup_usage_register_event(struct mem_cgroup memcg, if (ret) return ret; - mutex_lock(&memcg->thresholds_lock); + mutex_lock(&memcg->v1.thresholds_lock); if (type == _MEM) { - thresholds = &memcg->thresholds; + thresholds = &memcg->v1.thresholds; usage = mem_cgroup_usage(memcg, false); } else if (type == _MEMSWAP) { - thresholds = &memcg->memsw_thresholds; + thresholds = &memcg->v1.memsw_thresholds; usage = mem_cgroup_usage(memcg, true); } else BUG(); @@ -497,7 +497,7 @@ static int __mem_cgroup_usage_register_event(struct mem_cgroup memcg, synchronize_rcu(); unlock: - mutex_unlock(&memcg->thresholds_lock); + mutex_unlock(&memcg->v1.thresholds_lock); return ret; } @@ -522,13 +522,13 @@ static void __mem_cgroup_usage_unregister_event(struct mem_cgroup memcg, unsigned long usage; int i, j, size, entries; - mutex_lock(&memcg->thresholds_lock); + mutex_lock(&memcg->v1.thresholds_lock); if (type == _MEM) { - thresholds = &memcg->thresholds; + thresholds = &memcg->v1.thresholds; usage = mem_cgroup_usage(memcg, false); } else if (type == _MEMSWAP) { - thresholds = &memcg->memsw_thresholds; + thresholds = &memcg->v1.memsw_thresholds; usage = mem_cgroup_usage(memcg, true); } else BUG(); @@ -596,7 +596,7 @@ static void __mem_cgroup_usage_unregister_event(struct mem_cgroup memcg, thresholds->spare = NULL; } unlock: - mutex_unlock(&memcg->thresholds_lock); + mutex_unlock(&memcg->v1.thresholds_lock); } static void mem_cgroup_usage_unregister_event(struct mem_cgroup memcg, @@ -623,10 +623,10 @@ static int mem_cgroup_oom_register_event(struct mem_cgroup memcg, spin_lock(&memcg_oom_lock); event->eventfd = eventfd; - list_add(&event->list, &memcg->oom_notify); + list_add(&event->list, &memcg->v1.oom_notify); / already in OOM ? / - if (memcg->under_oom) + if (memcg->v1.under_oom) eventfd_signal(eventfd); spin_unlock(&memcg_oom_lock); @@ -640,7 +640,7 @@ static void mem_cgroup_oom_unregister_event(struct mem_cgroup memcg, spin_lock(&memcg_oom_lock); - list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) { + list_for_each_entry_safe(ev, tmp, &memcg->v1.oom_notify, list) { if (ev->eventfd == eventfd) { list_del(&ev->list); kfree(ev); @@ -709,7 +709,7 @@ static int memcg_event_wake(wait_queue_entry_t wait, unsigned int mode, side will require wqh->lock via remove_wait_queue(), * which we hold. / - spin_lock(&memcg->event_list_lock); + spin_lock(&memcg->v1.event_list_lock); if (!list_empty(&event->list)) { list_del_init(&event->list); / @@ -718,7 +718,7 @@ static int memcg_event_wake(wait_queue_entry_t wait, unsigned int mode, / schedule_work(&event->remove); } - spin_unlock(&memcg->event_list_lock); + spin_unlock(&memcg->v1.event_list_lock); } return 0; @@ -868,9 +868,9 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file of, vfs_poll(fd_file(efile), &event->pt); - spin_lock_irq(&memcg->event_list_lock); - list_add(&event->list, &memcg->event_list); - spin_unlock_irq(&memcg->event_list_lock); + spin_lock_irq(&memcg->v1.event_list_lock); + list_add(&event->list, &memcg->v1.event_list); + spin_unlock_irq(&memcg->v1.event_list_lock); return nbytes; out_put_css: @@ -884,10 +884,10 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file of, void memcg1_memcg_init(struct mem_cgroup memcg) { - INIT_LIST_HEAD(&memcg->oom_notify); - mutex_init(&memcg->thresholds_lock); - INIT_LIST_HEAD(&memcg->event_list); - spin_lock_init(&memcg->event_list_lock); + INIT_LIST_HEAD(&memcg->v1.oom_notify); + mutex_init(&memcg->v1.thresholds_lock); + INIT_LIST_HEAD(&memcg->v1.event_list); + spin_lock_init(&memcg->v1.event_list_lock); } void memcg1_css_offline(struct mem_cgroup memcg) @@ -899,12 +899,12 @@ void memcg1_css_offline(struct mem_cgroup memcg) Notify userspace about cgroup removing only after rmdir of cgroup * directory to avoid race between userspace and kernelspace. / - spin_lock_irq(&memcg->event_list_lock); - list_for_each_entry_safe(event, tmp, &memcg->event_list, list) { + spin_lock_irq(&memcg->v1.event_list_lock); + list_for_each_entry_safe(event, tmp, &memcg->v1.event_list, list) { list_del_init(&event->list); schedule_work(&event->remove); } - spin_unlock_irq(&memcg->event_list_lock); + spin_unlock_irq(&memcg->v1.event_list_lock); } / @@ -918,7 +918,7 @@ static bool mem_cgroup_oom_trylock(struct mem_cgroup memcg) spin_lock(&memcg_oom_lock); for_each_mem_cgroup_tree(iter, memcg) { - if (iter->oom_lock) { + if (iter->v1.oom_lock) { / * this subtree of our hierarchy is already locked * so we cannot give a lock. @@ -927,7 +927,7 @@ static bool mem_cgroup_oom_trylock(struct mem_cgroup memcg) mem_cgroup_iter_break(memcg, iter); break; } - iter->oom_lock = true; + iter->v1.oom_lock = true; } if (failed) { @@ -940,7 +940,7 @@ static bool mem_cgroup_oom_trylock(struct mem_cgroup memcg) mem_cgroup_iter_break(memcg, iter); break; } - iter->oom_lock = false; + iter->v1.oom_lock = false; } } else mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_); @@ -957,7 +957,7 @@ static void mem_cgroup_oom_unlock(struct mem_cgroup memcg) spin_lock(&memcg_oom_lock); mutex_release(&memcg_oom_lock_dep_map, _RET_IP_); for_each_mem_cgroup_tree(iter, memcg) - iter->oom_lock = false; + iter->v1.oom_lock = false; spin_unlock(&memcg_oom_lock); } @@ -967,7 +967,7 @@ static void mem_cgroup_mark_under_oom(struct mem_cgroup memcg) spin_lock(&memcg_oom_lock); for_each_mem_cgroup_tree(iter, memcg) - iter->under_oom++; + iter->v1.under_oom++; spin_unlock(&memcg_oom_lock); } @@ -981,8 +981,8 @@ static void mem_cgroup_unmark_under_oom(struct mem_cgroup memcg) / spin_lock(&memcg_oom_lock); for_each_mem_cgroup_tree(iter, memcg) - if (iter->under_oom > 0) - iter->under_oom--; + if (iter->v1.under_oom > 0) + iter->v1.under_oom--; spin_unlock(&memcg_oom_lock); } @@ -1012,14 +1012,14 @@ static int memcg_oom_wake_function(wait_queue_entry_t wait, void memcg1_oom_recover(struct mem_cgroup memcg) { /* - * For the following lockless ->under_oom test, the only required + * For the following lockless ->v1.under_oom test, the only required * guarantee is that it must see the state asserted by an OOM when * this function is called as a result of userland actions * triggered by the notification of the OOM. This is trivially * achieved by invoking mem_cgroup_mark_under_oom() before * triggering notification. / - if (memcg && memcg->under_oom) + if (memcg && memcg->v1.under_oom) __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg); } @@ -1100,7 +1100,7 @@ bool memcg1_oom_prepare(struct mem_cgroup memcg, bool locked) Please note that mem_cgroup_out_of_memory might fail to find a * victim and then we have to bail out from the charge path. / - if (READ_ONCE(memcg->oom_kill_disable)) { + if (READ_ONCE(memcg->v1.oom_kill_disable)) { if (current->in_user_fault) { css_get(&memcg->css); current->memcg_in_oom = memcg; @@ -1576,10 +1576,10 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state css, counter = &memcg->memsw; break; case _KMEM: - counter = &memcg->kmem; + counter = &memcg->v1.kmem; break; case _TCP: - counter = &memcg->tcpmem; + counter = &memcg->v1.tcpmem; break; default: BUG(); @@ -1619,11 +1619,11 @@ static int memcg_update_tcp_max(struct mem_cgroup memcg, unsigned long max) mutex_lock(&memcg_max_mutex); - ret = page_counter_set_max(&memcg->tcpmem, max); + ret = page_counter_set_max(&memcg->v1.tcpmem, max); if (ret) goto out; - if (!memcg->tcpmem_active) { + if (!memcg->v1.tcpmem_active) { / * The active flag needs to be written after the static_key * update. This is what guarantees that the socket activation @@ -1641,7 +1641,7 @@ static int memcg_update_tcp_max(struct mem_cgroup memcg, unsigned long max) patched in yet. / static_branch_inc(&memcg_sockets_enabled_key); - memcg->tcpmem_active = true; + memcg->v1.tcpmem_active = true; } out: mutex_unlock(&memcg_max_mutex); @@ -1710,10 +1710,10 @@ static ssize_t mem_cgroup_reset(struct kernfs_open_file of, char buf, counter = &memcg->memsw; break; case _KMEM: - counter = &memcg->kmem; + counter = &memcg->v1.kmem; break; case _TCP: - counter = &memcg->tcpmem; + counter = &memcg->v1.tcpmem; break; default: BUG(); @@ -1976,7 +1976,7 @@ static int mem_cgroup_swappiness_write(struct cgroup_subsys_state css, if (!mem_cgroup_is_root(memcg)) { pr_info_once("Per memcg swappiness does not exist in cgroup v2. " "See memory.reclaim or memory.swap.max there\n "); - WRITE_ONCE(memcg->swappiness, val); + WRITE_ONCE(memcg->v1.swappiness, val); } else WRITE_ONCE(vm_swappiness, val); @@ -1987,8 +1987,8 @@ static int mem_cgroup_oom_control_read(struct seq_file sf, void v) { struct mem_cgroup memcg = mem_cgroup_from_seq(sf); - seq_printf(sf, "oom_kill_disable %d\n", READ_ONCE(memcg->oom_kill_disable)); - seq_printf(sf, "under_oom %d\n", (bool)memcg->under_oom); + seq_printf(sf, "oom_kill_disable %d\n", READ_ONCE(memcg->v1.oom_kill_disable)); + seq_printf(sf, "under_oom %d\n", (bool)memcg->v1.under_oom); seq_printf(sf, "oom_kill %lu\n", atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL])); return 0; @@ -2007,7 +2007,7 @@ static int mem_cgroup_oom_control_write(struct cgroup_subsys_state css, if (mem_cgroup_is_root(memcg) \|\| !((val == 0) \|\| (val == 1))) return -EINVAL; - WRITE_ONCE(memcg->oom_kill_disable, val); + WRITE_ONCE(memcg->v1.oom_kill_disable, val); if (!val) memcg1_oom_recover(memcg); @@ -2183,9 +2183,9 @@ void memcg1_account_kmem(struct mem_cgroup memcg, int nr_pages) { if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) { if (nr_pages > 0) - page_counter_charge(&memcg->kmem, nr_pages); + page_counter_charge(&memcg->v1.kmem, nr_pages); else - page_counter_uncharge(&memcg->kmem, -nr_pages); + page_counter_uncharge(&memcg->v1.kmem, -nr_pages); } } @@ -2194,13 +2194,13 @@ bool memcg1_charge_skmem(struct mem_cgroup memcg, unsigned int nr_pages, { struct page_counter fail; - if (page_counter_try_charge(&memcg->tcpmem, nr_pages, &fail)) { - memcg->tcpmem_pressure = 0; + if (page_counter_try_charge(&memcg->v1.tcpmem, nr_pages, &fail)) { + memcg->v1.tcpmem_pressure = 0; return true; } - memcg->tcpmem_pressure = 1; + memcg->v1.tcpmem_pressure = 1; if (gfp_mask & __GFP_NOFAIL) { - page_counter_charge(&memcg->tcpmem, nr_pages); + page_counter_charge(&memcg->v1.tcpmem, nr_pages); return true; } return false; @@ -2208,12 +2208,12 @@ bool memcg1_charge_skmem(struct mem_cgroup memcg, unsigned int nr_pages, bool memcg1_alloc_events(struct mem_cgroup memcg) { - memcg->events_percpu = alloc_percpu_gfp(struct memcg1_events_percpu, + memcg->v1.events_percpu = alloc_percpu_gfp(struct memcg1_events_percpu, GFP_KERNEL_ACCOUNT); - return !!memcg->events_percpu; + return !!memcg->v1.events_percpu; } void memcg1_free_events(struct mem_cgroup memcg) { - free_percpu(memcg->events_percpu); + free_percpu(memcg->v1.events_percpu); } diff --git a/mm/memcontrol-v1.h b/mm/memcontrol-v1.h index 0952b2a783e52..cc41aa22af019 100644 --- a/mm/memcontrol-v1.h +++ b/mm/memcontrol-v1.h @@ -74,13 +74,13 @@ void reparent_memcg_state_local(struct mem_cgroup memcg, void memcg1_account_kmem(struct mem_cgroup memcg, int nr_pages); static inline bool memcg1_tcpmem_active(struct mem_cgroup memcg) { - return memcg->tcpmem_active; + return memcg->v1.tcpmem_active; } bool memcg1_charge_skmem(struct mem_cgroup memcg, unsigned int nr_pages, gfp_t gfp_mask); static inline void memcg1_uncharge_skmem(struct mem_cgroup memcg, unsigned int nr_pages) { - page_counter_uncharge(&memcg->tcpmem, nr_pages); + page_counter_uncharge(&memcg->v1.tcpmem, nr_pages); } extern struct cftype memsw_files[]; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 4d00748c8a5b8..4c883956d84ab 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1882,8 +1882,8 @@ void mem_cgroup_print_oom_meminfo(struct mem_cgroup memcg) K((u64)page_counter_read(&memcg->memsw)), K((u64)memcg->memsw.max), memcg->memsw.failcnt); pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n", - K((u64)page_counter_read(&memcg->kmem)), - K((u64)memcg->kmem.max), memcg->kmem.failcnt); + K((u64)page_counter_read(&memcg->v1.kmem)), + K((u64)memcg->v1.kmem.max), memcg->v1.kmem.failcnt); } #endif @@ -4300,13 +4300,13 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state parent_css) page_counter_init(&memcg->memory, &parent->memory, memcg_on_dfl); page_counter_init(&memcg->swap, &parent->swap, false); #ifdef CONFIG_MEMCG_V1 - WRITE_ONCE(memcg->swappiness, mem_cgroup_swappiness(parent)); + WRITE_ONCE(memcg->v1.swappiness, mem_cgroup_swappiness(parent)); memcg->memory.track_failcnt = !memcg_on_dfl; memcg->memsw.track_failcnt = !memcg_on_dfl; - WRITE_ONCE(memcg->oom_kill_disable, READ_ONCE(parent->oom_kill_disable)); - page_counter_init(&memcg->kmem, &parent->kmem, false); - page_counter_init(&memcg->tcpmem, &parent->tcpmem, false); - memcg->tcpmem.track_failcnt = !memcg_on_dfl; + WRITE_ONCE(memcg->v1.oom_kill_disable, READ_ONCE(parent->v1.oom_kill_disable)); + page_counter_init(&memcg->v1.kmem, &parent->v1.kmem, false); + page_counter_init(&memcg->v1.tcpmem, &parent->v1.tcpmem, false); + memcg->v1.tcpmem.track_failcnt = !memcg_on_dfl; #endif } else { init_memcg_stats(); @@ -4314,8 +4314,8 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state parent_css) page_counter_init(&memcg->memory, NULL, true); page_counter_init(&memcg->swap, NULL, false); #ifdef CONFIG_MEMCG_V1 - page_counter_init(&memcg->kmem, NULL, false); - page_counter_init(&memcg->tcpmem, NULL, false); + page_counter_init(&memcg->v1.kmem, NULL, false); + page_counter_init(&memcg->v1.tcpmem, NULL, false); #endif root_mem_cgroup = memcg; return &memcg->css; @@ -4492,8 +4492,8 @@ static void mem_cgroup_css_reset(struct cgroup_subsys_state css) WRITE_ONCE(memcg->zswap_writeback, true); #endif #ifdef CONFIG_MEMCG_V1 - page_counter_set_max(&memcg->kmem, PAGE_COUNTER_MAX); - page_counter_set_max(&memcg->tcpmem, PAGE_COUNTER_MAX); + page_counter_set_max(&memcg->v1.kmem, PAGE_COUNTER_MAX); + page_counter_set_max(&memcg->v1.tcpmem, PAGE_COUNTER_MAX); #endif page_counter_set_min(&memcg->memory, 0); page_counter_set_low(&memcg->memory, 0); diff --git a/mm/swap.h b/mm/swap.h index d5bf21f517dce..dc54f9a123567 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -87,7 +87,7 @@ static inline int mem_cgroup_swappiness(const struct mem_cgroup memcg) #ifdef CONFIG_MEMCG_V1 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg)) - return READ_ONCE(memcg->swappiness); + return READ_ONCE(memcg->v1.swappiness); #endif return READ_ONCE(vm_swappiness); }
3/2	2026/09/18 03:16	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 11584 output: 36 thoughts: 1086 Thoughts: Patch Analysis: WorthFuzzing = TRUE Okay, the patch is in review, and it's time to assess its fuzzing worthiness. Let's break this down. First, it adds a note to the documentation. Fine, documentation changes generally don't trigger fuzzing unless they expose a new API. But the meat of it is this: it's refactoring the `mem_cgroup` structure for the v1 memory controller. Specifically: it introduces a `struct mem_cgroup_v1` and embeds it within the main `struct mem_cgroup` under the `CONFIG_MEMCG_V1` conditional. It then updates all the references to the v1 fields – `kmem`, `tcpmem`, and others – to go through the new `v1` member. Now, according to the fuzzing guidelines, we never blindly trust "no functional change" claims, especially in refactoring. Any alteration to reachable executable code necessitates fuzzing. So, let's see if this meets that bar. Section 1 explicitly highlights the need to fuzz code even labeled as "cleanups" or "refactorings". The key here is that the guidelines say: "Return WorthFuzzing=true whenever the patch touches reachable executable code, including: ... Refactorings and Code Cleanups: Any restructuring of reachable data structures, helper abstractions, or algorithm flows." That hits the nail on the head. We have a restructuring of a reachable data structure – the `mem_cgroup` struct! It is absolutely a core data structure. Okay, is this reachable code? YES! The modifications are scattered across core memory management code in `mm/memcontrol.c`, `mm/memcontrol-v1.c`, networking code via `include/net/sock.h`, and even `mm/swap.h`. That is all stuff that is definitely reachable in the standard QEMU or syzkaller environments. The negative criteria for not fuzzing don't apply here. It's not documentation changes, not unreachable hardware, not unreachable execution paths, it's core C code in the kernel. Therefore, this must be fuzzed. WorthFuzzing is TRUE. We need to check the git log and diff with our tools to get the details.
4/2	2026/09/18 03:16	tool	grepper	0m Args: { "Expression": "struct mem_cgroup_v1", "PathPrefix": "include/linux/memcontrol.h" } Results: { "Output": "include/linux/memcontrol.h=179=struct obj_cgroup {\n--\ninclude/linux/memcontrol.h-199- /\ninclude/linux/memcontrol.h:200:struct mem_cgroup_v1 {\ninclude/linux/memcontrol.h-201-\tstruct page_counter kmem;\n--\ninclude/linux/memcontrol.h=233=struct mem_cgroup {\n--\ninclude/linux/memcontrol.h-310-#ifdef CONFIG_MEMCG_V1\ninclude/linux/memcontrol.h:311:\tstruct mem_cgroup_v1 v1;\ninclude/linux/memcontrol.h-312-#endif / CONFIG_MEMCG_V1 */\n" }
5/2	2026/09/18 03:16	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 13391 output: 30 thoughts: 18 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: Kconfig Dive for Memory Control Group V1 Alright, time to get my hands dirty. My initial thought is to zero in on the Kconfig files. Specifically, I need to verify the availability and implications of `CONFIG_MEMCG_V1`. I'll need to double-check that it's defined, of course, but more importantly, I need to understand its dependencies and relationships with other related configurations. My past experiences have taught me that these seemingly simple flags often have hidden impacts on other kernel subsystems and features. I'll be looking for things like: * Dependencies: What other features are automatically enabled or disabled when `CONFIG_MEMCG_V1` is selected? Are there any unexpected conflicts? Are there specific prerequisites? * Default Behavior: Is `CONFIG_MEMCG_V1` enabled by default for specific architectures or distributions? If so, which ones, and why? I need to understand the reasoning behind any default choices. * Alternatives: Does `CONFIG_MEMCG_V1` have any modern alternatives? Are there any deprecation notices or warnings? Is the v2 implementation preferred or recommended over the v1 implementation? * Documentation: What is the specific documentation or comments present in Kconfig describing this setting? Does it explain the implications, the performance characteristics, and the supported use cases? I need to fully understand its intended purpose. * Kernel Code implications: Finally, I'll consider how these settings affect the various features, options, and behaviors of the kernel memory management.
6/2	2026/09/18 03:16	tool	grepper	0m Args: { "Expression": "config MEMCG_V1", "PathPrefix": "init/Kconfig" } Results: { "Output": "init/Kconfig=1094=config MEMCG_NMI_SAFETY_REQUIRES_ATOMIC\n--\ninit/Kconfig-1100-\ninit/Kconfig:1101:config MEMCG_V1\ninit/Kconfig-1102-\tbool \"Legacy cgroup v1 memory controller\"\n" }
7/2	2026/09/18 03:16	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 13872 output: 33 thoughts: 20 Thoughts: Here's my take on the situation: Diving into the Kernel Configuration Landscape Okay, let's get down to brass tacks. I need to understand this section of the kernel configuration. My instinct tells me to start around line 1101 within `init/Kconfig`. That's often a good starting point for initialization-related settings. I'm expecting to find some crucial defaults, dependencies, or maybe some conditional logic that controls how the kernel boots or initializes itself. I'm keen to see the specific variables and how they link to other configurations. Gotta understand the building blocks before I can refine or contribute. Let's see what gems are hidden there.
8/2	2026/09/18 03:16	tool	read-file	0m Args: { "File": "init/Kconfig", "FirstLine": 1095, "LineCount": 35 } Results: { "Contents": "1095:\t\tbool\n1096:\t\tdepends on MEMCG\n1097:\t\tdepends on HAVE_NMI\n1098:\t\tdepends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS \u0026\u0026 ARCH_HAVE_NMI_SAFE_CMPXCHG\n1099:\t\tdefault y\n1100:\t\n1101:\tconfig MEMCG_V1\n1102:\t\tbool \"Legacy cgroup v1 memory controller\"\n1103:\t\tdepends on MEMCG\n1104:\t\tdefault n\n1105:\t\thelp\n1106:\t\t Legacy cgroup v1 memory controller which has been deprecated by\n1107:\t\t cgroup v2 implementation. The v1 is there for legacy applications\n1108:\t\t which haven't migrated to the new cgroup v2 interface yet. If you\n1109:\t\t do not have any such application then you are completely fine leaving\n1110:\t\t this option disabled.\n1111:\t\n1112:\t\t Please note that feature set of the legacy memory controller is likely\n1113:\t\t going to shrink due to deprecation process. New deployments with v1\n1114:\t\t controller are highly discouraged.\n1115:\t\n1116:\t\t Say N if unsure.\n1117:\t\n1118:\tconfig BLK_CGROUP\n1119:\t\tbool \"IO controller\"\n1120:\t\tdepends on BLOCK\n1121:\t\tdefault n\n1122:\t\thelp\n1123:\t\tGeneric block IO controller cgroup interface. This is the common\n1124:\t\tcgroup interface which should be used by various IO controlling\n1125:\t\tpolicies.\n1126:\t\n1127:\t\tCurrently, CFQ IO scheduler uses it to recognize task groups and\n1128:\t\tcontrol disk bandwidth allocation (proportional time slice allocation)\n1129:\t\tto such task groups. It is also used by bio throttling logic in\n" }
9/2	2026/09/18 03:16	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 14580 output: 28 thoughts: 22 Thoughts: Here's my summary, as though I were thinking through the problem: Dependencies and Verification Okay, so `MEMCG_V1` relies on `MEMCG`. Makes sense, they're likely closely related in the hierarchy or functionality. My first instinct, as always, is to establish the foundation. We need to confirm that `MEMCG` is functioning as expected before we even begin to assess `MEMCG_V1`. That dependency is critical, so let's start with a thorough check of `MEMCG` itself. I need to understand its current state, any existing issues, and its overall reliability. This is a standard procedure; we can't build on a shaky base.
10/2	2026/09/18 03:16	tool	grepper	0m Args: { "Expression": "config MEMCG$", "PathPrefix": "init/Kconfig" } Results: { "Output": "init/Kconfig=1068=config CGROUP_FAVOR_DYNMODS\n--\ninit/Kconfig-1077-\ninit/Kconfig:1078:config MEMCG\ninit/Kconfig-1079-\tbool \"Memory controller\"\n" }
11/2	2026/09/18 03:16	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 14856 output: 33 thoughts: 17 Thoughts: Here's my summary, as if I were thinking these thoughts: Examining the Core Configuration File Alright, let's dive into the `init/Kconfig` file. I'm specifically interested in line 1075 right now. I suspect we're likely dealing with a fundamental configuration option here, potentially something critical to the early initialization process or a core kernel feature. Knowing where it is in the file should give me a good handle on its general context. Let's see what we've got.
12/2	2026/09/18 03:16	tool	read-file	0m Args: { "File": "init/Kconfig", "FirstLine": 1075, "LineCount": 25 } Results: { "Contents": "1075:\t\n1076:\t\t Say N if unsure.\n1077:\t\n1078:\tconfig MEMCG\n1079:\t\tbool \"Memory controller\"\n1080:\t\tselect PAGE_COUNTER\n1081:\t\tselect EVENTFD\n1082:\t\tselect SLAB_OBJ_EXT\n1083:\t\tselect VM_EVENT_COUNTERS\n1084:\t\thelp\n1085:\t\t Provides control over the memory footprint of tasks in a cgroup.\n1086:\t\n1087:\tconfig MEMCG_NMI_UNSAFE\n1088:\t\tbool\n1089:\t\tdepends on MEMCG\n1090:\t\tdepends on HAVE_NMI\n1091:\t\tdepends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS \u0026\u0026 !ARCH_HAVE_NMI_SAFE_CMPXCHG\n1092:\t\tdefault y\n1093:\t\n1094:\tconfig MEMCG_NMI_SAFETY_REQUIRES_ATOMIC\n1095:\t\tbool\n1096:\t\tdepends on MEMCG\n1097:\t\tdepends on HAVE_NMI\n1098:\t\tdepends on !ARCH_HAS_NMI_SAFE_THIS_CPU_OPS \u0026\u0026 ARCH_HAVE_NMI_SAFE_CMPXCHG\n1099:\t\tdefault y\n" }
13/2	2026/09/18 03:16	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 15370 output: 27 thoughts: 673 Thoughts: Analyzing the CONFIG_MEMCG_V1 Dependency Okay, so `MEMCG_V1` clearly depends on `MEMCG`. I need to figure out the scope of this dependency, so let's start by looking at any other configs within this patch. I see the `#ifdef CONFIG_MEMCG_V1` directive, so that's the key. Now, I need to do a thorough review, diving into the diff and surrounding files to see where else this configuration variable is used. I've got the documentation file `Documentation/admin-guide/cgroup-v1/memory.rst`, that's a good starting point. Then, in `include/linux/memcontrol.h`, there's a `struct mem_cgroup_v1`, which is conditionally defined. Okay, good. And, also in `include/net/sock.h`, the function `mem_cgroup_sk_under_memory_pressure` is gated by the same config. Now I'll dive into the core implementation in `mm/memcontrol-v1.c`. I see a whole slew of functions prefixed with `memcg1_`, functions related to OOM handling, and functions for managing memory statistics. This includes threshold management, event handling, memory charging and uncharging, and so on. There are also functions for reading and writing control values, and functions for accounting kernel memory. In `mm/memcontrol-v1.h`, I see some static inline functions, `memcg1_tcpmem_active` and `memcg1_uncharge_skmem`. Looks like helpers for common tasks. Finally, in `mm/memcontrol.c`, there are some general memory cgroup functions like `mem_cgroup_print_oom_meminfo`, `mem_cgroup_css_alloc`, and `mem_cgroup_css_reset`, although these seem to be general memory cgroup code, rather than specific to v1. Also, `mm/swap.h` has a conditional definition of `mem_cgroup_swappiness`. I need to quickly check the `mm/Makefile` to see how this file is actually compiled. This will solidify my understanding of when this code gets included in the build.
14/2	2026/09/18 03:17	tool	grepper	0m Args: { "Expression": "memcontrol-v1", "PathPrefix": "mm/" } Results: { "Output": "mm/Makefile=28=KCOV_INSTRUMENT_memcontrol.o := n\nmm/Makefile:29:KCOV_INSTRUMENT_memcontrol-v1.o := n\nmm/Makefile-30-KCOV_INSTRUMENT_mmzone.o := n\n--\nmm/Makefile=104=obj-$(CONFIG_LIVEUPDATE_MEMFD) += memfd_luo.o\nmm/Makefile:105:obj-$(CONFIG_MEMCG_V1) += memcontrol-v1.o\nmm/Makefile-106-obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o\n--\nmm/memcontrol-v1.c-17-#include \"swap_table.h\"\nmm/memcontrol-v1.c:18:#include \"memcontrol-v1.h\"\nmm/memcontrol-v1.c-19-\n--\nmm/memcontrol.c-71-#include \"slab.h\"\nmm/memcontrol.c:72:#include \"memcontrol-v1.h\"\nmm/memcontrol.c-73-\n--\nmm/vmpressure.c-11- * Tree-mode (cgroup v1 userspace eventfd) bookkeeping lives in\nmm/vmpressure.c:12: * mm/memcontrol-v1.c; this file holds the shared code and the in-kernel\nmm/vmpressure.c-13- * (tree=false) socket-pressure path that runs on cgroup v2.\n" }
15/2	2026/09/18 03:17	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 16926 output: 30 thoughts: 49 Thoughts: Okay, here's my interpretation of those thoughts, presented as my own mental process: Makefile Anomalies and Memory Control Hmm, now that I'm reviewing this makefile, I'm spotting something potentially significant. I see `KCOV_INSTRUMENT_memcontrol-v1.o := n` and `KCOV_INSTRUMENT_memcontrol.o := n` in `mm/Makefile`! Wait a minute, what's with these seemingly unrelated entries? Are we disabling instrumentation for all memory control related objects with a seemingly unrelated key? I need to check this line closely. The way this is structured... is it a build-time conditional? Are there any dependencies in the makefile that would affect this? Let me look at the surrounding code and try to figure out what's going on! This could be a significant oversight!
16/2	2026/09/18 03:17	tool	read-file	0m Args: { "File": "mm/Makefile", "FirstLine": 20, "LineCount": 20 } Results: { "Contents": " 20:\t# These files are disabled because they produce non-interesting and/or\n 21:\t# flaky coverage that is not a function of syscall inputs. E.g. slab is out of\n 22:\t# free pages, or a task is migrated between nodes.\n 23:\tKCOV_INSTRUMENT_slab_common.o := n\n 24:\tKCOV_INSTRUMENT_slub.o := n\n 25:\tKCOV_INSTRUMENT_page_alloc.o := n\n 26:\tKCOV_INSTRUMENT_debug-pagealloc.o := n\n 27:\tKCOV_INSTRUMENT_kmemleak.o := n\n 28:\tKCOV_INSTRUMENT_memcontrol.o := n\n 29:\tKCOV_INSTRUMENT_memcontrol-v1.o := n\n 30:\tKCOV_INSTRUMENT_mmzone.o := n\n 31:\tKCOV_INSTRUMENT_vmstat.o := n\n 32:\tKCOV_INSTRUMENT_failslab.o := n\n 33:\t\n 34:\tCFLAGS_init-mm.o += -Wno-override-init\n 35:\t\n 36:\tmmu-y\t\t\t:= nommu.o\n 37:\tmmu-$(CONFIG_MMU)\t:= highmem.o memory.o mincore.o \\\n 38:\t\t\t\t mlock.o mmap.o mmu_gather.o mprotect.o mremap.o \\\n 39:\t\t\t\t msync.o page_vma_mapped.o pagewalk.o \\\n" }
17/2	2026/09/18 03:17	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 17596 output: 31 thoughts: 1102 Thoughts: Analyzing the Impact of KCOV Disable on Syzkaller's Effectiveness Okay, so the initial concern is: if `KCOV_INSTRUMENT_memcontrol-v1.o := n`, does that mean syzkaller loses coverage, or is it still targeted? Let's break this down. First, I need to revisit the "WorthFuzzing" criteria. Reading through Sections 1 and 2, specifically the negative criteria ("WHEN TO RETURN WorthFuzzing=false"), I see that a KCOV disable is not listed. The criteria state "ONLY IF all modified code falls strictly into one or more of these categories", and that list focuses on code changes themselves, not build configurations. Syzkaller still does target the kernel, even with KCOV disabled in some compilation units; it will trigger execution through syscalls, generating faults, and using assertions which still provide valuable bug detection. The positive criteria in Section 3, ("WHEN TO RETURN WorthFuzzing=true") emphasize reachable executable code. That's the key. Modifications in core subsystems are always good targets. Now, let's consider `FocusSymbols` from Section 4. Can functions in `memcontrol-v1.o` or `memcontrol.o` be valid focus symbols? Even if `KCOV_INSTRUMENT` is 'n'? Syzkaller uses vmlinux symbol table addresses from things like `/proc/kallsyms` to build its symbol filters. If KCOV is disabled for an object file, does syzkaller receive KCOV PC trace for functions inside that object file? `KCOV` is the mechanism syzkaller uses for coverage feedback. If an object file has `KCOV_INSTRUMENT_foo.o := n`, then the GCC/Clang compiler doesn't insert those `__sanitizer_cov_trace_pc` calls into the object file, and therefore syzkaller won't receive coverage data for those functions. This is the critical point. So, here's the problem: if syzkaller is focused on a symbol in an object file where KCOV is disabled, no coverage will ever be reported for that symbol. That defeats the purpose of focusing! But... is `KCOV_INSTRUMENT` actually disabled in our kernel build? Or is it just a default in upstream? Let's check `mm/Makefile`. We need to examine whether `KCOV_INSTRUMENT_memcontrol-v1.o := n` is actually set, or if it has been overridden in our configuration. I should check the git log or do a blame on `mm/Makefile`. This is a crucial step!
18/2	2026/09/18 03:17	tool	grepper	0m Args: { "Expression": "KCOV_INSTRUMENT_memcontrol", "PathPrefix": "mm/" } Results: { "Output": "mm/Makefile=27=KCOV_INSTRUMENT_kmemleak.o := n\nmm/Makefile:28:KCOV_INSTRUMENT_memcontrol.o := n\nmm/Makefile:29:KCOV_INSTRUMENT_memcontrol-v1.o := n\nmm/Makefile-30-KCOV_INSTRUMENT_mmzone.o := n\n" }
19/2	2026/09/18 03:17	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 19419 output: 30 thoughts: 13 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Analyzing the mm/Makefile History with `git log` Okay, so I'm trying to pinpoint something related to `mm/Makefile` and I need to understand its evolution around a specific time frame. My immediate thought is to reach for `git log`. I want to quickly grasp the changes that have happened in this critical Makefile. Specifically, I'm thinking of focusing the `git log` output on that particular file. I'll probably start with a fairly basic `git log` command, maybe adding some options to enhance readability, like `--oneline` or `--graph` to get a visual representation of the branches involved. I might need to filter the log with a date range if I have a rough idea of when the change I am interested in occurred. If I need to be more specific, I'll probably look into `--author` or `--grep` to narrow down the search. Essentially, I'm using `git log` as my primary tool to dissect the history and understand the context surrounding the target of my investigation.
20/2	2026/09/18 03:17	tool	grepper	0m Args: { "Expression": "memcontrol-v1.o", "PathPrefix": "mm/Makefile" } Results: { "Output": "mm/Makefile=28=KCOV_INSTRUMENT_memcontrol.o := n\nmm/Makefile:29:KCOV_INSTRUMENT_memcontrol-v1.o := n\nmm/Makefile-30-KCOV_INSTRUMENT_mmzone.o := n\n--\nmm/Makefile=104=obj-$(CONFIG_LIVEUPDATE_MEMFD) += memfd_luo.o\nmm/Makefile:105:obj-$(CONFIG_MEMCG_V1) += memcontrol-v1.o\nmm/Makefile-106-obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o\n" }
21/2	2026/09/18 03:17	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 19859 output: 26 thoughts: 175 Thoughts: Investigating Unexpected Caller Functions in Memory Control Okay, so I'm looking at this patch and my initial thought is, "Hold on, are there actually any call sites for these modified functions outside of the `mm/memcontrol-v1.o` and `mm/memcontrol.o` modules?" It seems unusual, and I need to verify that I'm not missing anything. I need to make sure I have a complete picture. My focus is on understanding the scope of this change. Let's trace these calls. Specifically, I'm going to pinpoint exactly where those modified inline functions or symbols are being invoked. Looking at the patch itself, I see this in `include/net/sock.h`: ```c static inline bool mem_cgroup_sk_under_memory_pressure(const struct sock sk) { ... #ifdef CONFIG_MEMCG_V1 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) return !memcg->v1.tcpmem_pressure; #endif / CONFIG_MEMCG_V1 / ... } ``` Okay, so the `mem_cgroup_sk_under_memory_pressure` function is defined here. Now, I need to know where this* function is called. That's the key. I need to trace this call chain and ensure it behaves as expected given the changes. Let's dig in and find those call sites.
22/2	2026/09/18 03:17	tool	grepper	0m Args: { "Expression": "mem_cgroup_sk_under_memory_pressure" } Results: { "Output": "include/net/proto_memory.h=29=static inline bool sk_under_memory_pressure(const struct sock sk)\n--\ninclude/net/proto_memory.h-34-\tif (mem_cgroup_sk_enabled(sk) \u0026\u0026\ninclude/net/proto_memory.h:35:\t mem_cgroup_sk_under_memory_pressure(sk))\ninclude/net/proto_memory.h-36-\t\treturn true;\n--\ninclude/net/sock.h=2697=static inline bool mem_cgroup_sk_enabled(const struct sock sk)\n--\ninclude/net/sock.h-2701-\ninclude/net/sock.h:2702:static inline bool mem_cgroup_sk_under_memory_pressure(const struct sock sk)\ninclude/net/sock.h-2703-{\n--\ninclude/net/sock.h=2728=static inline bool mem_cgroup_sk_enabled(const struct sock sk)\n--\ninclude/net/sock.h-2732-\ninclude/net/sock.h:2733:static inline bool mem_cgroup_sk_under_memory_pressure(const struct sock sk)\ninclude/net/sock.h-2734-{\n--\ninclude/net/tcp.h=299=static inline bool tcp_under_memory_pressure(const struct sock sk)\n--\ninclude/net/tcp.h-301-\tif (mem_cgroup_sk_enabled(sk) \u0026\u0026\ninclude/net/tcp.h:302:\t mem_cgroup_sk_under_memory_pressure(sk))\ninclude/net/tcp.h-303-\t\treturn true;\n" }
23/2	2026/09/18 03:17	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 20818 output: 22 thoughts: 29 Thoughts: Okay, here's the summary, rendered as if it's my own thought process: Deeper Dive into `mem_cgroup_swappiness` Right, let me just pause and make absolutely sure I've got the full picture here. We've been talking about `mem_cgroup_swappiness` and its role. Before I go any further, I need to understand its actual usage within the kernel's memory management code. I'm going to quickly check where this specific function is called within `mm/swap.h` itself. That's the best way to get a solid grasp of how it's integrated and what other functions or data structures it interacts with. Understanding its callsites is critical. I'm after the direct usage context here, which can then give me insight into the broader implications and the subtle behaviours of memory cgroup management as a whole. No assumptions, just the raw code; that's the only reliable path to insight.
24/2	2026/09/18 03:17	tool	grepper	0m Args: { "Expression": "mem_cgroup_swappiness" } Results: { "Output": "mm/memcontrol-v1.c=1886=void memcg1_stat_format(struct mem_cgroup memcg, struct seq_buf s)\n--\nmm/memcontrol-v1.c-1959-\nmm/memcontrol-v1.c:1960:static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state css,\nmm/memcontrol-v1.c-1961-\t\t\t\t struct cftype cft)\n--\nmm/memcontrol-v1.c-1964-\nmm/memcontrol-v1.c:1965:\treturn mem_cgroup_swappiness(memcg);\nmm/memcontrol-v1.c-1966-}\nmm/memcontrol-v1.c-1967-\nmm/memcontrol-v1.c:1968:static int mem_cgroup_swappiness_write(struct cgroup_subsys_state css,\nmm/memcontrol-v1.c-1969-\t\t\t\t struct cftype cft, u64 val)\n--\nmm/memcontrol-v1.c=2028=struct cftype mem_cgroup_legacy_files[] = {\n--\nmm/memcontrol-v1.c-2076-\t\t.name = \"swappiness\",\nmm/memcontrol-v1.c:2077:\t\t.read_u64 = mem_cgroup_swappiness_read,\nmm/memcontrol-v1.c:2078:\t\t.write_u64 = mem_cgroup_swappiness_write,\nmm/memcontrol-v1.c-2079-\t},\n--\nmm/memcontrol.c=1901=unsigned long mem_cgroup_get_max(const struct mem_cgroup memcg)\n--\nmm/memcontrol.c-1905-\tif (do_memsw_account()) {\nmm/memcontrol.c:1906:\t\tif (mem_cgroup_swappiness(memcg)) {\nmm/memcontrol.c-1907-\t\t\t/ Calculate swap excess capacity from memsw limit /\n--\nmm/memcontrol.c-1912-\t} else {\nmm/memcontrol.c:1913:\t\tif (mem_cgroup_swappiness(memcg))\nmm/memcontrol.c-1914-\t\t\tmax += min(READ_ONCE(memcg-\u003eswap.max),\n--\nmm/memcontrol.c=4281=mem_cgroup_css_alloc(struct cgroup_subsys_state parent_css)\n--\nmm/memcontrol.c-4302-#ifdef CONFIG_MEMCG_V1\nmm/memcontrol.c:4303:\t\tWRITE_ONCE(memcg-\u003ev1.swappiness, mem_cgroup_swappiness(parent));\nmm/memcontrol.c-4304-\t\tmemcg-\u003ememory.track_failcnt = !memcg_on_dfl;\n--\nmm/swap.h-6-#include \u003clinux/mm.h\u003e /* for PAGE_SHIFT /\nmm/swap.h:7:#include \u003clinux/memcontrol.h\u003e / for mem_cgroup_swappiness() /\nmm/swap.h-8-#include \u003clinux/swap.h\u003e / for MAX_SWAPFILES_SHIFT, struct swap_info_struct /\n--\nmm/swap.h=83=extern int vm_swappiness;\nmm/swap.h-84-\nmm/swap.h:85:static inline int mem_cgroup_swappiness(const struct mem_cgroup memcg)\nmm/swap.h-86-{\n--\nmm/vmscan.c=223=static int sc_swappiness(struct scan_control sc, struct mem_cgroup memcg)\n--\nmm/vmscan.c-226-\t\treturn sc-\u003eproactive_swappiness;\nmm/vmscan.c:227:\treturn mem_cgroup_swappiness(memcg);\nmm/vmscan.c-228-}\n--\nmm/vmscan.c=4670=static void try_to_inc_max_seq_nowalk(struct mem_cgroup memcg,\n--\nmm/vmscan.c-4674-\tstruct lru_gen_mm_state *mm_state = get_mm_state(lruvec);\nmm/vmscan.c:4675:\tint swappiness = mem_cgroup_swappiness(memcg);\nmm/vmscan.c-4676-\tDEFINE_MAX_SEQ(lruvec);\n" }
25/2	2026/09/18 03:17	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 22241 output: 22 thoughts: 500 Thoughts: Investigating the Interaction of FocusSymbols, KCOV, and memcontrol-v1.c Okay, so I'm trying to understand something here. Can `FocusSymbols` potentially include functions defined within `mm/memcontrol-v1.c` and `mm/memcontrol.c`? That's the core question. Let me first make sure I remember what functions are even in `memcontrol-v1.c`. Alright, looks like it's got a bunch: `memcg_write_event_control`, `mem_cgroup_swappiness_write`, `mem_cgroup_oom_control_write`, and so on. Now, a red flag popped up: why was KCOV disabled for this file in the `mm/Makefile`? KCOV's a pretty important tool, especially for something like syzkaller. I'm wondering, does syzkaller even use KCOV? Yep, it does. But here's the kicker: does syzkaller ignore `FocusSymbols` when KCOV is off, or does syzkaller rely on `FocusSymbols` to select testcases based on syscalls that cover these symbols? This is critical. If `KCOV_INSTRUMENT_memcontrol-v1.o := n` is set, does that mean no tests can trigger functions in `memcontrol-v1.o` for KCOV? Of course! Because that setting would prevent the compiler from inserting `__sanitizer_cov_trace_pc` into those functions. But wait... is `KCOV_INSTRUMENT_memcontrol-v1.o := n` always active? Or can it be overridden somewhere? Is KCOV disabled in the syzkaller kernel configs, or is the setting overridden there? My brain is starting to churn! I know syzkaller builds its own kernels with its own configs, but does it usually edit Makefiles? I don't think so... usually it does not. Okay, I need to take a different approach. Let's check places like `net/core/sock.c` or other areas that might call `memcg1_charge_skmem` or `sk_under_memory_pressure`. I'll just grep for `memcg1_charge_skmem` and see where it shows up. That should give me a better understanding of how these functions are used.
26/2	2026/09/18 03:17	tool	grepper	0m Args: { "Expression": "memcg1_charge_skmem" } Results: { "Output": "mm/memcontrol-v1.c=2182=void memcg1_account_kmem(struct mem_cgroup memcg, int nr_pages)\n--\nmm/memcontrol-v1.c-2191-\nmm/memcontrol-v1.c:2192:bool memcg1_charge_skmem(struct mem_cgroup memcg, unsigned int nr_pages,\nmm/memcontrol-v1.c-2193-\t\t\t gfp_t gfp_mask)\n--\nmm/memcontrol-v1.h=75=static inline bool memcg1_tcpmem_active(struct mem_cgroup memcg)\n--\nmm/memcontrol-v1.h-78-}\nmm/memcontrol-v1.h:79:bool memcg1_charge_skmem(struct mem_cgroup memcg, unsigned int nr_pages,\nmm/memcontrol-v1.h-80-\t\t\t gfp_t gfp_mask);\n--\nmm/memcontrol-v1.h=116=static inline bool memcg1_tcpmem_active(struct mem_cgroup memcg) { return false; }\nmm/memcontrol-v1.h:117:static inline bool memcg1_charge_skmem(struct mem_cgroup memcg, unsigned int nr_pages,\nmm/memcontrol-v1.h-118-\t\t\t\t gfp_t gfp_mask) { return true; }\n--\nmm/memcontrol.c=5736=bool mem_cgroup_sk_charge(const struct sock *sk, unsigned int nr_pages,\n--\nmm/memcontrol.c-5741-\tif (!cgroup_subsys_on_dfl(memory_cgrp_subsys))\nmm/memcontrol.c:5742:\t\treturn memcg1_charge_skmem(memcg, nr_pages, gfp_mask);\nmm/memcontrol.c-5743-\n" }
27/2	2026/09/18 03:17	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 23780 output: 22 thoughts: 14 Thoughts: Here's my thought process, as if I were considering this question: Investigating the Call Sites of `mem_cgroup_sk_charge` Alright, so the task at hand is to figure out where `mem_cgroup_sk_charge` is being called within the kernel. This sounds like an interesting performance investigation, likely related to memory accounting within cgroups. I'll need to trace its usage. First, I need to consider my options. I could use `cscope` or `ctags` if this is a particularly complex kernel structure. Perhaps `grep` or `git grep` could provide a quick and dirty answer. Since I know this is a critical function, I'll likely need to analyze the results carefully, excluding any false positives. `perf` with the right set of probes would be another powerful option. In fact, if the system is running, I'd probably start with `perf probe` to see if I can get some immediate insights into dynamic calls. I should also think about the context. What is this function supposed to be doing? If it relates to socket memory charging within a memory cgroup, then I'm going to be looking at network-related code paths, or perhaps at the memory reclaim subsystem as related to socket buffers. I’d want to keep an eye out for places where socket memory usage is tracked. I'll mentally prepare myself to examine both the networking stack and the memory management code, especially around `sk_buff` management and the cgroup interfaces. Maybe I can find some clues from the relevant commits too. Essentially, I need to start with some broad search techniques, and then narrow down the scope based on the initial results. I want to build a call graph mentally, or through tools. This should give me a good handle on where this function is really getting used. My gut feeling is that it's going to be in the critical path for socket memory management, but I could be wrong, and I need to be methodical in my investigation.
28/2	2026/09/18 03:17	tool	grepper	0m Args: { "Expression": "mem_cgroup_sk_charge" } Results: { "Output": "include/linux/memcontrol.h=1673=void mem_cgroup_sk_inherit(const struct sock sk, struct sock newsk);\ninclude/linux/memcontrol.h:1674:bool mem_cgroup_sk_charge(const struct sock sk, unsigned int nr_pages,\ninclude/linux/memcontrol.h-1675-\t\t\t gfp_t gfp_mask);\n--\ninclude/linux/memcontrol.h=1733=static inline void mem_cgroup_sk_inherit(const struct sock sk, struct sock newsk)\n--\ninclude/linux/memcontrol.h-1736-\ninclude/linux/memcontrol.h:1737:static inline bool mem_cgroup_sk_charge(const struct sock sk,\ninclude/linux/memcontrol.h-1738-\t\t\t\t\tunsigned int nr_pages,\n--\nmm/memcontrol.c=5711=void mem_cgroup_sk_inherit(const struct sock sk, struct sock newsk)\n--\nmm/memcontrol.c-5727-/*\nmm/memcontrol.c:5728: mem_cgroup_sk_charge - charge socket memory\nmm/memcontrol.c-5729- * @sk: socket in memcg to charge\n--\nmm/memcontrol.c-5735- /\nmm/memcontrol.c:5736:bool mem_cgroup_sk_charge(const struct sock sk, unsigned int nr_pages,\nmm/memcontrol.c-5737-\t\t\t gfp_t gfp_mask)\n--\nnet/core/sock.c=1030=static int sock_reserve_memory(struct sock sk, int bytes)\n--\nnet/core/sock.c-1044-\t/ pre-charge to memcg /\nnet/core/sock.c:1045:\tcharged = mem_cgroup_sk_charge(sk, pages,\nnet/core/sock.c-1046-\t\t\t\t GFP_KERNEL \| __GFP_RETRY_MAYFAIL);\n--\nnet/core/sock.c=3336=int __sk_mem_raise_allocated(struct sock sk, int size, int amt, int kind)\n--\nnet/core/sock.c-3348-\t\tmemcg_enabled = true;\nnet/core/sock.c:3349:\t\tcharged = mem_cgroup_sk_charge(sk, amt, gfp_memcg_charge());\nnet/core/sock.c-3350-\t\tif (!charged)\n--\nnet/core/sock.c-3426-\t\t\tif (memcg_enabled \u0026\u0026 !charged)\nnet/core/sock.c:3427:\t\t\t\tmem_cgroup_sk_charge(sk, amt,\nnet/core/sock.c-3428-\t\t\t\t\t\t gfp_memcg_charge() \| __GFP_NOFAIL);\n--\nnet/core/sock.c=3501=void __sk_charge(struct sock sk, gfp_t gfp)\n--\nnet/core/sock.c-3512-\t\tif (amt)\nnet/core/sock.c:3513:\t\t\tmem_cgroup_sk_charge(sk, amt, gfp);\nnet/core/sock.c-3514-\t}\n--\nnet/ipv4/tcp.c=906=void sk_forced_mem_schedule(struct sock sk, int size)\n--\nnet/ipv4/tcp.c-917-\tif (mem_cgroup_sk_enabled(sk))\nnet/ipv4/tcp.c:918:\t\tmem_cgroup_sk_charge(sk, amt, gfp_memcg_charge() \| __GFP_NOFAIL);\nnet/ipv4/tcp.c-919-\n--\nnet/mptcp/protocol.c=4310=static void mptcp_graft_subflows(struct sock *sk)\n--\nnet/mptcp/protocol.c-4368-\t\tif (amt)\nnet/mptcp/protocol.c:4369:\t\t\tmem_cgroup_sk_charge(sk, amt, gfp);\nnet/mptcp/protocol.c-4370-\t}\n" }
29/2	2026/09/18 03:17	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 25297 output: 21 thoughts: 24 Thoughts: Okay, here's my take on those thoughts, framed as an expert's self-reflection: Deep Dive on Memory Pressure Indicators Alright, so we're looking at some performance indicators, and I'm immediately thinking, "Let's dig a little deeper here." My gut tells me these aren't the only pieces of the puzzle when we're dealing with memory pressure scenarios. So, I need to check those specific kernel parameters – `sk_under_memory_pressure` and `tcp_under_memory_pressure`. I know that these are key signals. If we are seeing problems, checking these values are a crucial first step. I suspect that there are many more signals that will be useful, but checking these first will save time and determine if we are barking up the wrong tree. This should allow me to formulate a plan.
30/2	2026/09/18 03:17	tool	grepper	0m Args: { "Expression": "tcp_under_memory_pressure" } Results: { "Output": "include/net/tcp.h=296=extern unsigned long tcp_memory_pressure;\n--\ninclude/net/tcp.h-298-/* optimized version of sk_under_memory_pressure() for TCP sockets /\ninclude/net/tcp.h:299:static inline bool tcp_under_memory_pressure(const struct sock sk)\ninclude/net/tcp.h-300-{\n--\ninclude/net/tcp.h=1814=static inline bool tcp_rmem_pressure(const struct sock sk)\n--\ninclude/net/tcp.h-1817-\ninclude/net/tcp.h:1818:\tif (tcp_under_memory_pressure(sk))\ninclude/net/tcp.h-1819-\t\treturn true;\n--\nnet/ipv4/tcp_input.c=700=static void tcp_grow_window(struct sock sk, const struct sk_buff skb,\n--\nnet/ipv4/tcp_input.c-711-\t/ Check #1 /\nnet/ipv4/tcp_input.c:712:\tif (!tcp_under_memory_pressure(sk)) {\nnet/ipv4/tcp_input.c-713-\t\tunsigned int truesize = truesize_adjust(adjust, skb);\n--\nnet/ipv4/tcp_input.c=778=static void tcp_clamp_window(struct sock sk)\n--\nnet/ipv4/tcp_input.c-789-\t !(sk-\u003esk_userlocks \u0026 SOCK_RCVBUF_LOCK) \u0026\u0026\nnet/ipv4/tcp_input.c:790:\t !tcp_under_memory_pressure(sk) \u0026\u0026\nnet/ipv4/tcp_input.c-791-\t sk_memory_allocated(sk) \u003c sk_prot_mem_limits(sk, 0)) {\n--\nnet/ipv4/tcp_input.c=5939=static bool tcp_prune_ofo_queue(struct sock sk, const struct sk_buff in_skb)\n--\nnet/ipv4/tcp_input.c-5965-\t\t\tif (tcp_can_ingest(sk, in_skb) \u0026\u0026\nnet/ipv4/tcp_input.c:5966:\t\t\t !tcp_under_memory_pressure(sk))\nnet/ipv4/tcp_input.c-5967-\t\t\t\tbreak;\n--\nnet/ipv4/tcp_input.c=5993=static int tcp_prune_queue(struct sock sk, const struct sk_buff in_skb)\n--\nnet/ipv4/tcp_input.c-6004-\t\ttcp_clamp_window(sk);\nnet/ipv4/tcp_input.c:6005:\telse if (tcp_under_memory_pressure(sk))\nnet/ipv4/tcp_input.c-6006-\t\ttcp_adjust_rcv_ssthresh(sk);\n--\nnet/ipv4/tcp_input.c=6040=static bool tcp_should_expand_sndbuf(struct sock sk)\n--\nnet/ipv4/tcp_input.c-6050-\t/ If we are under global TCP memory pressure, do not expand. /\nnet/ipv4/tcp_input.c:6051:\tif (tcp_under_memory_pressure(sk)) {\nnet/ipv4/tcp_input.c-6052-\t\tint unused_mem = sk_unused_reserved_mem(sk);\n--\nnet/ipv4/tcp_output.c=3314=u32 __tcp_select_window(struct sock sk)\n--\nnet/ipv4/tcp_output.c-3351-\nnet/ipv4/tcp_output.c:3352:\t\tif (tcp_under_memory_pressure(sk))\nnet/ipv4/tcp_output.c-3353-\t\t\ttcp_adjust_rcv_ssthresh(sk);\n--\nnet/ipv4/tcp_output.c-3410-\nnet/ipv4/tcp_output.c:3411:\t\tif (tcp_under_memory_pressure(sk))\nnet/ipv4/tcp_output.c-3412-\t\t\ttcp_adjust_rcv_ssthresh(sk);\n--\nnet/ipv4/tcp_output.c=3801=void tcp_send_fin(struct sock sk)\n--\nnet/ipv4/tcp_output.c-3811-\ttskb = tail;\nnet/ipv4/tcp_output.c:3812:\tif (!tskb \u0026\u0026 tcp_under_memory_pressure(sk))\nnet/ipv4/tcp_output.c-3813-\t\ttskb = skb_rb_last(\u0026sk-\u003etcp_rtx_queue);\n--\nnet/mptcp/protocol.h=869=static inline bool mptcp_epollin_ready(const struct sock sk)\n--\nnet/mptcp/protocol.h-879-\treturn (data_avail \u003e= sk-\u003esk_rcvlowat) \|\|\nnet/mptcp/protocol.h:880:\t\ttcp_under_memory_pressure(sk);\nnet/mptcp/protocol.h-881-}\n" }
31/2	2026/09/18 03:17	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 26821 output: 39 thoughts: 52 Thoughts: Analyzing `mm/memcontrol-v1.c` Function Entrypoints and Visibility Okay, let's take a closer look at the `mm/memcontrol-v1.c` file. My immediate thought is to understand the scope and interactions of the code within it. I need to identify which functions are entry points, basically, the externally visible interfaces that drive the memory control functionality. More importantly, what are the functions defined inside this file, and what is their visibility – are they internal helpers, or are they exported and thus callable from elsewhere in the kernel? I need to build a mental map of this module's architecture and how it integrates with the rest of the memory management subsystem. This is the first step in understanding the overall design.
32/2	2026/09/18 03:17	tool	grepper	0m Args: { "Expression": "^[a-zA-Z_].\\(", "PathPrefix": "mm/memcontrol-v1.c" } Results:* { "Output": "mm/memcontrol-v1.c=78=static struct lockdep_map memcg_oom_lock_dep_map = {\n--\nmm/memcontrol-v1.c-82-\nmm/memcontrol-v1.c:83:DEFINE_SPINLOCK(memcg_oom_lock);\nmm/memcontrol-v1.c-84-\nmm/memcontrol-v1.c:85:static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state css,\nmm/memcontrol-v1.c-86-\t\t\t\tstruct cftype cft)\n--\nmm/memcontrol-v1.c-91-#ifdef CONFIG_MMU\nmm/memcontrol-v1.c:92:static int mem_cgroup_move_charge_write(struct cgroup_subsys_state css,\nmm/memcontrol-v1.c-93-\t\t\t\t struct cftype cft, u64 val)\n--\nmm/memcontrol-v1.c-103-#else\nmm/memcontrol-v1.c:104:static int mem_cgroup_move_charge_write(struct cgroup_subsys_state css,\nmm/memcontrol-v1.c-105-\t\t\t\t struct cftype cft, u64 val)\n--\nmm/memcontrol-v1.c-110-\nmm/memcontrol-v1.c:111:static unsigned long mem_cgroup_usage(struct mem_cgroup memcg, bool swap)\nmm/memcontrol-v1.c-112-{\n--\nmm/memcontrol-v1.c-132-\nmm/memcontrol-v1.c:133:static void __mem_cgroup_threshold(struct mem_cgroup memcg, bool swap)\nmm/memcontrol-v1.c-134-{\n--\nmm/memcontrol-v1.c-183-\nmm/memcontrol-v1.c:184:static void mem_cgroup_threshold(struct mem_cgroup memcg)\nmm/memcontrol-v1.c-185-{\n--\nmm/memcontrol-v1.c=203=struct memcg1_events_percpu {\n--\nmm/memcontrol-v1.c-207-\nmm/memcontrol-v1.c:208:static void memcg1_charge_statistics(struct mem_cgroup memcg, int nr_pages)\nmm/memcontrol-v1.c-209-{\n--\nmm/memcontrol-v1.c-222-\nmm/memcontrol-v1.c:223:static bool memcg1_event_ratelimit(struct mem_cgroup memcg)\nmm/memcontrol-v1.c-224-{\n--\nmm/memcontrol-v1.c-237-\nmm/memcontrol-v1.c:238:static void memcg1_check_events(struct mem_cgroup memcg)\nmm/memcontrol-v1.c-239-{\n--\nmm/memcontrol-v1.c-246-\nmm/memcontrol-v1.c:247:void memcg1_commit_charge(struct folio folio, struct mem_cgroup memcg)\nmm/memcontrol-v1.c-248-{\n--\nmm/memcontrol-v1.c-268- /\nmm/memcontrol-v1.c:269:void __memcg1_swapout(struct folio folio, struct swap_cluster_info ci)\nmm/memcontrol-v1.c-270-{\n--\nmm/memcontrol-v1.c-340- /\nmm/memcontrol-v1.c:341:void memcg1_swapin(struct folio folio)\nmm/memcontrol-v1.c-342-{\n--\nmm/memcontrol-v1.c-378-\nmm/memcontrol-v1.c:379:void memcg1_uncharge_batch(struct mem_cgroup memcg, unsigned long pgpgout,\nmm/memcontrol-v1.c-380-\t\t\t unsigned long nr_memory)\n--\nmm/memcontrol-v1.c-390-\nmm/memcontrol-v1.c:391:static int compare_thresholds(const void a, const void b)\nmm/memcontrol-v1.c-392-{\n--\nmm/memcontrol-v1.c-404-\nmm/memcontrol-v1.c:405:static void mem_cgroup_oom_notify_cb(struct mem_cgroup memcg)\nmm/memcontrol-v1.c-406-{\n--\nmm/memcontrol-v1.c-416-\nmm/memcontrol-v1.c:417:static void mem_cgroup_oom_notify(struct mem_cgroup memcg)\nmm/memcontrol-v1.c-418-{\n--\nmm/memcontrol-v1.c-424-\nmm/memcontrol-v1.c:425:static int __mem_cgroup_usage_register_event(struct mem_cgroup memcg,\nmm/memcontrol-v1.c-426-\tstruct eventfd_ctx eventfd, const char args, enum res_type type)\n--\nmm/memcontrol-v1.c-504-\nmm/memcontrol-v1.c:505:static int mem_cgroup_usage_register_event(struct mem_cgroup memcg,\nmm/memcontrol-v1.c-506-\tstruct eventfd_ctx eventfd, const char args)\n--\nmm/memcontrol-v1.c-510-\nmm/memcontrol-v1.c:511:static int memsw_cgroup_usage_register_event(struct mem_cgroup memcg,\nmm/memcontrol-v1.c-512-\tstruct eventfd_ctx eventfd, const char args)\n--\nmm/memcontrol-v1.c-516-\nmm/memcontrol-v1.c:517:static void __mem_cgroup_usage_unregister_event(struct mem_cgroup memcg,\nmm/memcontrol-v1.c-518-\tstruct eventfd_ctx eventfd, enum res_type type)\n--\nmm/memcontrol-v1.c-601-\nmm/memcontrol-v1.c:602:static void mem_cgroup_usage_unregister_event(struct mem_cgroup memcg,\nmm/memcontrol-v1.c-603-\tstruct eventfd_ctx eventfd)\n--\nmm/memcontrol-v1.c-607-\nmm/memcontrol-v1.c:608:static void memsw_cgroup_usage_unregister_event(struct mem_cgroup memcg,\nmm/memcontrol-v1.c-609-\tstruct eventfd_ctx eventfd)\n--\nmm/memcontrol-v1.c-613-\nmm/memcontrol-v1.c:614:static int mem_cgroup_oom_register_event(struct mem_cgroup memcg,\nmm/memcontrol-v1.c-615-\tstruct eventfd_ctx eventfd, const char args)\n--\nmm/memcontrol-v1.c-635-\nmm/memcontrol-v1.c:636:static void mem_cgroup_oom_unregister_event(struct mem_cgroup memcg,\nmm/memcontrol-v1.c-637-\tstruct eventfd_ctx eventfd)\n--\nmm/memcontrol-v1.c-670- /\nmm/memcontrol-v1.c:671:static void memcg_event_remove(struct work_struct work)\nmm/memcontrol-v1.c-672-{\n--\nmm/memcontrol-v1.c-693- /\nmm/memcontrol-v1.c:694:static int memcg_event_wake(wait_queue_entry_t wait, unsigned int mode,\nmm/memcontrol-v1.c-695-\t\t\t int sync, void key)\n--\nmm/memcontrol-v1.c-726-\nmm/memcontrol-v1.c:727:static void memcg_event_ptable_queue_proc(struct file file,\nmm/memcontrol-v1.c-728-\t\twait_queue_head_t wqh, poll_table pt)\n--\nmm/memcontrol-v1.c-744- /\nmm/memcontrol-v1.c:745:static ssize_t memcg_write_event_control(struct kernfs_open_file of,\nmm/memcontrol-v1.c-746-\t\t\t\t\t char buf, size_t nbytes, loff_t off)\n--\nmm/memcontrol-v1.c-884-\nmm/memcontrol-v1.c:885:void memcg1_memcg_init(struct mem_cgroup memcg)\nmm/memcontrol-v1.c-886-{\n--\nmm/memcontrol-v1.c-892-\nmm/memcontrol-v1.c:893:void memcg1_css_offline(struct mem_cgroup memcg)\nmm/memcontrol-v1.c-894-{\n--\nmm/memcontrol-v1.c-913- /\nmm/memcontrol-v1.c:914:static bool mem_cgroup_oom_trylock(struct mem_cgroup memcg)\nmm/memcontrol-v1.c-915-{\n--\nmm/memcontrol-v1.c-952-\nmm/memcontrol-v1.c:953:static void mem_cgroup_oom_unlock(struct mem_cgroup memcg)\nmm/memcontrol-v1.c-954-{\n--\nmm/memcontrol-v1.c-963-\nmm/memcontrol-v1.c:964:static void mem_cgroup_mark_under_oom(struct mem_cgroup memcg)\nmm/memcontrol-v1.c-965-{\n--\nmm/memcontrol-v1.c-973-\nmm/memcontrol-v1.c:974:static void mem_cgroup_unmark_under_oom(struct mem_cgroup memcg)\nmm/memcontrol-v1.c-975-{\n--\nmm/memcontrol-v1.c-988-\nmm/memcontrol-v1.c:989:static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);\nmm/memcontrol-v1.c-990-\nmm/memcontrol-v1.c=991=struct oom_wait_info {\n--\nmm/memcontrol-v1.c-995-\nmm/memcontrol-v1.c:996:static int memcg_oom_wake_function(wait_queue_entry_t wait,\nmm/memcontrol-v1.c-997-\tunsigned int mode, int sync, void arg)\n--\nmm/memcontrol-v1.c-1011-\nmm/memcontrol-v1.c:1012:void memcg1_oom_recover(struct mem_cgroup memcg)\nmm/memcontrol-v1.c-1013-{\n--\nmm/memcontrol-v1.c-1042- /\nmm/memcontrol-v1.c:1043:bool mem_cgroup_oom_synchronize(bool handle)\nmm/memcontrol-v1.c-1044-{\n--\nmm/memcontrol-v1.c-1082-\nmm/memcontrol-v1.c:1083:bool memcg1_oom_prepare(struct mem_cgroup memcg, bool locked)\nmm/memcontrol-v1.c-1084-{\n--\nmm/memcontrol-v1.c-1122-\nmm/memcontrol-v1.c:1123:void memcg1_oom_finish(struct mem_cgroup memcg, bool locked)\nmm/memcontrol-v1.c-1124-{\n--\nmm/memcontrol-v1.c-1152- /\nmm/memcontrol-v1.c:1153:static const unsigned int vmpressure_level_critical_prio = ilog2(100 / 10);\nmm/memcontrol-v1.c-1154-\n--\nmm/memcontrol-v1.c=1174=struct vmpressure_event {\n--\nmm/memcontrol-v1.c-1180-\nmm/memcontrol-v1.c:1181:static struct vmpressure work_to_vmpressure(struct work_struct work)\nmm/memcontrol-v1.c-1182-{\n--\nmm/memcontrol-v1.c-1185-\nmm/memcontrol-v1.c:1186:static struct vmpressure vmpressure_parent(struct vmpressure vmpr)\nmm/memcontrol-v1.c-1187-{\n--\nmm/memcontrol-v1.c-1195-\nmm/memcontrol-v1.c:1196:static bool vmpressure_event(struct vmpressure vmpr,\nmm/memcontrol-v1.c-1197-\t\t\t const enum vmpressure_levels level,\n--\nmm/memcontrol-v1.c-1218-\nmm/memcontrol-v1.c:1219:static void vmpressure_work_fn(struct work_struct work)\nmm/memcontrol-v1.c-1220-{\n--\nmm/memcontrol-v1.c-1261- /\nmm/memcontrol-v1.c:1262:void vmpressure_v1_account_tree(struct vmpressure vmpr,\nmm/memcontrol-v1.c-1263-\t\t\t\tunsigned long scanned,\n--\nmm/memcontrol-v1.c-1275-\nmm/memcontrol-v1.c:1276:void vmpressure_v1_init(struct vmpressure vmpr)\nmm/memcontrol-v1.c-1277-{\n--\nmm/memcontrol-v1.c-1282-\nmm/memcontrol-v1.c:1283:void vmpressure_v1_cleanup(struct vmpressure vmpr)\nmm/memcontrol-v1.c-1284-{\n--\nmm/memcontrol-v1.c-1302- /\nmm/memcontrol-v1.c:1303:void vmpressure_prio(gfp_t gfp, struct mem_cgroup memcg, int prio)\nmm/memcontrol-v1.c-1304-{\n--\nmm/memcontrol-v1.c-1341- /\nmm/memcontrol-v1.c:1342:int vmpressure_register_event(struct mem_cgroup memcg,\nmm/memcontrol-v1.c-1343-\t\t\t struct eventfd_ctx eventfd, const char args)\n--\nmm/memcontrol-v1.c-1402- /\nmm/memcontrol-v1.c:1403:void vmpressure_unregister_event(struct mem_cgroup memcg,\nmm/memcontrol-v1.c-1404-\t\t\t\t struct eventfd_ctx eventfd)\n--\nmm/memcontrol-v1.c-1419-\nmm/memcontrol-v1.c:1420:static DEFINE_MUTEX(memcg_max_mutex);\nmm/memcontrol-v1.c-1421-\nmm/memcontrol-v1.c:1422:static int mem_cgroup_resize_max(struct mem_cgroup memcg,\nmm/memcontrol-v1.c-1423-\t\t\t\t unsigned long max, bool memsw)\n--\nmm/memcontrol-v1.c-1484- /\nmm/memcontrol-v1.c:1485:static int mem_cgroup_force_empty(struct mem_cgroup memcg)\nmm/memcontrol-v1.c-1486-{\n--\nmm/memcontrol-v1.c-1510-\nmm/memcontrol-v1.c:1511:static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file of,\nmm/memcontrol-v1.c-1512-\t\t\t\t\t char buf, size_t nbytes,\n--\nmm/memcontrol-v1.c-1521-\nmm/memcontrol-v1.c:1522:static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state css,\nmm/memcontrol-v1.c-1523-\t\t\t\t struct cftype cft)\n--\nmm/memcontrol-v1.c-1527-\nmm/memcontrol-v1.c:1528:static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state css,\nmm/memcontrol-v1.c-1529-\t\t\t\t struct cftype cft, u64 val)\n--\nmm/memcontrol-v1.c-1540-\nmm/memcontrol-v1.c:1541:static u64 mem_cgroup_soft_limit_read(struct cgroup_subsys_state css,\nmm/memcontrol-v1.c-1542-\t\t\t\t struct cftype cft)\n--\nmm/memcontrol-v1.c-1546-\nmm/memcontrol-v1.c:1547:static ssize_t mem_cgroup_soft_limit_write(struct kernfs_open_file of,\nmm/memcontrol-v1.c-1548-\t\t\t\t\t char buf, size_t nbytes, loff_t off)\n--\nmm/memcontrol-v1.c-1564-\nmm/memcontrol-v1.c:1565:static u64 mem_cgroup_read_u64(struct cgroup_subsys_state css,\nmm/memcontrol-v1.c-1566-\t\t\t struct cftype cft)\n--\nmm/memcontrol-v1.c-1609- /\nmm/memcontrol-v1.c:1610:static int mem_cgroup_dummy_seq_show(__always_unused struct seq_file m,\nmm/memcontrol-v1.c-1611-\t\t\t\t __always_unused void v)\n--\nmm/memcontrol-v1.c-1615-\nmm/memcontrol-v1.c:1616:static int memcg_update_tcp_max(struct mem_cgroup memcg, unsigned long max)\nmm/memcontrol-v1.c-1617-{\n--\nmm/memcontrol-v1.c-1654- /\nmm/memcontrol-v1.c:1655:static ssize_t mem_cgroup_write(struct kernfs_open_file of,\nmm/memcontrol-v1.c-1656-\t\t\t\tchar buf, size_t nbytes, loff_t off)\n--\nmm/memcontrol-v1.c-1698-\nmm/memcontrol-v1.c:1699:static ssize_t mem_cgroup_reset(struct kernfs_open_file of, char buf,\nmm/memcontrol-v1.c-1700-\t\t\t\tsize_t nbytes, loff_t off)\n--\nmm/memcontrol-v1.c-1741-\nmm/memcontrol-v1.c:1742:static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup memcg,\nmm/memcontrol-v1.c-1743-\t\t\t\tint nid, unsigned int lru_mask, bool tree)\n--\nmm/memcontrol-v1.c-1761-\nmm/memcontrol-v1.c:1762:static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup memcg,\nmm/memcontrol-v1.c-1763-\t\t\t\t\t unsigned int lru_mask,\n--\nmm/memcontrol-v1.c-1779-\nmm/memcontrol-v1.c:1780:static int memcg_numa_stat_show(struct seq_file m, void v)\nmm/memcontrol-v1.c-1781-{\n--\nmm/memcontrol-v1.c=1863=static const unsigned int memcg1_events[] = {\n--\nmm/memcontrol-v1.c-1869-\nmm/memcontrol-v1.c:1870:void reparent_memcg1_state_local(struct mem_cgroup memcg, struct mem_cgroup parent)\nmm/memcontrol-v1.c-1871-{\n--\nmm/memcontrol-v1.c-1877-\nmm/memcontrol-v1.c:1878:void reparent_memcg1_lruvec_state_local(struct mem_cgroup memcg, struct mem_cgroup parent)\nmm/memcontrol-v1.c-1879-{\n--\nmm/memcontrol-v1.c-1885-\nmm/memcontrol-v1.c:1886:void memcg1_stat_format(struct mem_cgroup memcg, struct seq_buf s)\nmm/memcontrol-v1.c-1887-{\n--\nmm/memcontrol-v1.c-1959-\nmm/memcontrol-v1.c:1960:static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state css,\nmm/memcontrol-v1.c-1961-\t\t\t\t struct cftype cft)\n--\nmm/memcontrol-v1.c-1967-\nmm/memcontrol-v1.c:1968:static int mem_cgroup_swappiness_write(struct cgroup_subsys_state css,\nmm/memcontrol-v1.c-1969-\t\t\t\t struct cftype cft, u64 val)\n--\nmm/memcontrol-v1.c-1985-\nmm/memcontrol-v1.c:1986:static int mem_cgroup_oom_control_read(struct seq_file sf, void v)\nmm/memcontrol-v1.c-1987-{\n--\nmm/memcontrol-v1.c-1996-\nmm/memcontrol-v1.c:1997:static int mem_cgroup_oom_control_write(struct cgroup_subsys_state css,\nmm/memcontrol-v1.c-1998-\tstruct cftype cft, u64 val)\n--\nmm/memcontrol-v1.c-2017-#ifdef CONFIG_SLUB_DEBUG\nmm/memcontrol-v1.c:2018:static int mem_cgroup_slab_show(struct seq_file m, void p)\nmm/memcontrol-v1.c-2019-{\n--\nmm/memcontrol-v1.c=2155=struct cftype memsw_files[] = {\n--\nmm/memcontrol-v1.c-2181-\nmm/memcontrol-v1.c:2182:void memcg1_account_kmem(struct mem_cgroup memcg, int nr_pages)\nmm/memcontrol-v1.c-2183-{\n--\nmm/memcontrol-v1.c-2191-\nmm/memcontrol-v1.c:2192:bool memcg1_charge_skmem(struct mem_cgroup memcg, unsigned int nr_pages,\nmm/memcontrol-v1.c-2193-\t\t\t gfp_t gfp_mask)\n--\nmm/memcontrol-v1.c-2208-\nmm/memcontrol-v1.c:2209:bool memcg1_alloc_events(struct mem_cgroup memcg)\nmm/memcontrol-v1.c-2210-{\n--\nmm/memcontrol-v1.c-2215-\nmm/memcontrol-v1.c:2216:void memcg1_free_events(struct mem_cgroup *memcg)\nmm/memcontrol-v1.c-2217-{\n" }
33/2	2026/09/18 03:17	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 33327 output: 22 thoughts: 1177 Thoughts: Analyzing Memcg v1 Functionality and Potential Focus Symbols Okay, let's break this down. My initial thought process is to understand the changes and identify key functions. I see a bunch of potential focus symbols related to memcg v1: `memcg1_account_kmem`, `memcg1_charge_skmem`, `memcg1_oom_prepare`, `memcg1_oom_recover`, `memcg1_uncharge_batch`, `memcg_write_event_control`, `memcg_update_tcp_max`, `mem_cgroup_swappiness_write`, and `mem_cgroup_oom_control_write`. First, I quickly checked how `mem_cgroup_sk_charge` in `net/core/sock.c` interacts with `memcg1_charge_skmem`, confirming its critical role in socket memory charging under memory pressure. Then, I quickly made sure I could locate it's definition in `mm/memcontrol.c`. Now, let's dig into the specific modifications in `mm/memcontrol.c`. I found some functions were modified: `mem_cgroup_print_oom_meminfo`, `mem_cgroup_css_alloc`, and `mem_cgroup_css_reset`. I now turn my attention to `mm/memcontrol-v1.c`, and I see a much more extensive list of changes: `__mem_cgroup_threshold`, `memcg1_charge_statistics`, `memcg1_event_ratelimit`, `memcg1_uncharge_batch`, `mem_cgroup_oom_notify_cb`, `__mem_cgroup_usage_register_event`, `__mem_cgroup_usage_unregister_event`, `mem_cgroup_oom_register_event`, `mem_cgroup_oom_unregister_event`, `memcg_event_wake`, `memcg_write_event_control`, `memcg1_memcg_init`, `memcg1_css_offline`, `mem_cgroup_oom_trylock`, `mem_cgroup_oom_unlock`, `mem_cgroup_mark_under_oom`, `mem_cgroup_unmark_under_oom`, `memcg1_oom_recover`, `memcg1_oom_prepare`, `mem_cgroup_read_u64`, `memcg_update_tcp_max`, `mem_cgroup_reset`, `mem_cgroup_swappiness_write`, `mem_cgroup_oom_control_read`, `mem_cgroup_oom_control_write`, `memcg1_account_kmem`, `memcg1_charge_skmem`, `memcg1_alloc_events`, and `memcg1_free_events`. That's quite a comprehensive set of v1-specific functions. Now comes the crucial part: I need to filter out any "ubiquitous" functions to avoid diluting the fuzzing effort. I know from past experience, and this section clarifies, that I need to be careful with functions like memory allocators, page fault handlers, and core synchronization primitives. Those are too generic. So, let's analyze the functions in context. `mem_cgroup_css_alloc` is called when creating a cgroup, which is a fairly common operation, so potentially a bad focus. `memcg_write_event_control` is directly tied to the v1-specific `cgroup.event_control` file, making it a good focus candidate. Similarly, `memcg_update_tcp_max` handles writing the TCP limit in v1, and that's specific. `mem_cgroup_swappiness_write` deals with `memory.swappiness` and `mem_cgroup_oom_control_write` deals with `memory.oom_control`, also all specific. `memcg1_charge_skmem` is part of charging skmem in memcg v1. And `memcg1_account_kmem` is part of kmem accounting. `memcg1_oom_prepare` is v1 OOM handling. `memcg1_uncharge_batch` is on my radar; I need to verify its call sites regarding uncharging pages in v1 to make sure it is not ubiquitous.
34/2	2026/09/18 03:18	tool	grepper	0m Args: { "Expression": "memcg1_uncharge_batch" } Results: { "Output": "mm/memcontrol-v1.c=341=void memcg1_swapin(struct folio folio)\n--\nmm/memcontrol-v1.c-378-\nmm/memcontrol-v1.c:379:void memcg1_uncharge_batch(struct mem_cgroup memcg, unsigned long pgpgout,\nmm/memcontrol-v1.c-380-\t\t\t unsigned long nr_memory)\n--\nmm/memcontrol-v1.h=63=void memcg1_commit_charge(struct folio folio, struct mem_cgroup memcg);\nmm/memcontrol-v1.h:64:void memcg1_uncharge_batch(struct mem_cgroup memcg, unsigned long pgpgout,\nmm/memcontrol-v1.h-65-\t\t\t unsigned long nr_memory);\n--\nmm/memcontrol-v1.h=106=static inline void memcg1_commit_charge(struct folio folio,\n--\nmm/memcontrol-v1.h-108-\nmm/memcontrol-v1.h:109:static inline void memcg1_uncharge_batch(struct mem_cgroup memcg,\nmm/memcontrol-v1.h-110-\t\t\t\t\t unsigned long pgpgout,\n--\nmm/memcontrol.c=5429=static void uncharge_batch(const struct uncharge_gather ug)\n--\nmm/memcontrol.c-5443-\nmm/memcontrol.c:5444:\tmemcg1_uncharge_batch(memcg, ug-\u003epgpgout, ug-\u003enr_memory);\nmm/memcontrol.c-5445-\trcu_read_unlock();\n" }
35/2	2026/09/18 03:18	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 35903 output: 22 thoughts: 104 Thoughts: Analyzing Potential Hot Paths in Memory Management Okay, so `uncharge_batch` gets called during page uncharging, which happens when pretty much everything frees up memory. That makes `memcg1_uncharge_batch` a prime candidate for a lifecycle hot-path. Gotta keep an eye on that one. And, thinking further, what about `mem_cgroup_swappiness` and `memcg1_charge_statistics`? Those could be pretty active too, depending on how aggressively we're swapping and tracking memory usage within cgroups. Worth investigating their behavior under load. Let's not forget `memcg1_account_kmem`. That seems important in accounting for kernel memory. The best way to understand its real impact is to check its call sites. Gotta see who's relying on `memcg1_account_kmem`. Diving into the caller list now...
36/2	2026/09/18 03:18	tool	grepper	0m Args: { "Expression": "memcg1_account_kmem" } Results: { "Output": "mm/memcontrol-v1.c=2155=struct cftype memsw_files[] = {\n--\nmm/memcontrol-v1.c-2181-\nmm/memcontrol-v1.c:2182:void memcg1_account_kmem(struct mem_cgroup memcg, int nr_pages)\nmm/memcontrol-v1.c-2183-{\n--\nmm/memcontrol-v1.h=71=void reparent_memcg_state_local(struct mem_cgroup memcg,\n--\nmm/memcontrol-v1.h-73-\nmm/memcontrol-v1.h:74:void memcg1_account_kmem(struct mem_cgroup memcg, int nr_pages);\nmm/memcontrol-v1.h-75-static inline bool memcg1_tcpmem_active(struct mem_cgroup memcg)\n--\nmm/memcontrol-v1.h=113=static inline void memcg1_stat_format(struct mem_cgroup memcg, struct seq_buf s) {}\nmm/memcontrol-v1.h-114-\nmm/memcontrol-v1.h:115:static inline void memcg1_account_kmem(struct mem_cgroup memcg, int nr_pages) {}\nmm/memcontrol-v1.h-116-static inline bool memcg1_tcpmem_active(struct mem_cgroup memcg) { return false; }\n--\nmm/memcontrol.c=142=static void memcg_uncharge_kmem(struct mem_cgroup memcg, unsigned int nr_pages)\n--\nmm/memcontrol.c-144-\tmod_memcg_state(memcg, MEMCG_KMEM, -nr_pages);\nmm/memcontrol.c:145:\tmemcg1_account_kmem(memcg, -nr_pages);\nmm/memcontrol.c-146-\tif (!mem_cgroup_is_root(memcg))\n--\nmm/memcontrol.c=3192=static void obj_cgroup_uncharge_pages(struct obj_cgroup objcg,\n--\nmm/memcontrol.c-3199-\taccount_kmem_nmi_safe(memcg, -nr_pages);\nmm/memcontrol.c:3200:\tmemcg1_account_kmem(memcg, -nr_pages);\nmm/memcontrol.c-3201-\tif (!mem_cgroup_is_root(memcg))\n--\nmm/memcontrol.c=3215=static int obj_cgroup_charge_pages(struct obj_cgroup objcg, gfp_t gfp,\n--\nmm/memcontrol.c-3227-\taccount_kmem_nmi_safe(memcg, nr_pages);\nmm/memcontrol.c:3228:\tmemcg1_account_kmem(memcg, nr_pages);\nmm/memcontrol.c-3229-out:\n--\nmm/memcontrol.c=5429=static void uncharge_batch(const struct uncharge_gather ug)\n--\nmm/memcontrol.c-5438-\t\t\tmod_memcg_state(memcg, MEMCG_KMEM, -ug-\u003enr_kmem);\nmm/memcontrol.c:5439:\t\t\tmemcg1_account_kmem(memcg, -ug-\u003enr_kmem);\nmm/memcontrol.c-5440-\t\t}\n" }
37/2	2026/09/18 03:18	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 37106 output: 33 thoughts: 605 Thoughts: My Thoughts on Specific cgroup v1 Memory Controller Entrypoints Okay, so I'm digging into how the memory controller works in cgroup v1. I've confirmed that `memcg1_account_kmem` is a fundamental part of the allocation lifecycle, called from `obj_cgroup_charge_pages`, which is involved in slab allocations. It's ubiquitous, basically. But I'm trying to pinpoint those specific, non-ubiquitous feature-specific functions and entrypoints. Here's what I've identified: 1. `memcg_write_event_control`: This is the entrypoint for writing to the `event_control` file, setting up event notifications like thresholds, OOM, and vmpressure for cgroup v1. 2. `memcg_update_tcp_max`: This one configures the TCP memory limit within the cgroup v1 framework, affecting `memory.kmem.tcp.limit_in_bytes`. 3. `mem_cgroup_swappiness_write`: Clearly, it's used to configure swappiness via the `memory.swappiness` file. 4. `mem_cgroup_oom_control_write`: This handles configuring the OOM control behavior, likely writing to the `memory.oom_control` file in cgroup v1. 5. `mem_cgroup_oom_register_event`: This is the function responsible for eventfd registration for OOM events, specifically in the cgroup v1 world. 6. `__mem_cgroup_usage_register_event`: Similarly, this one handles eventfd registration for memory threshold events in cgroup v1. 7. `mem_cgroup_reset`: This is the function responsible for resetting stats and max counters in cgroup v1, likely writing to `memory.max_usage_in_bytes`, and others. 8. `memcg1_oom_recover`: This function seems to handle recovering from OOM conditions, particularly when oom\_kill\_disable is off or when memory gets freed. 9. `mem_cgroup_print_oom_meminfo`: Prints the OOM meminfo during OOM killer runs. 10. `mem_cgroup_css_reset`: This resets cgroup css state. Now, I'm looking at `memcg1_charge_skmem`. Is it also ubiquitous? It looks like when socket memory is charged in cgroup v1 via `mem_cgroup_sk_charge`, it calls `memcg1_charge_skmem`. Sockets might show up a lot in the syzkaller networking tests, but that’s still specific to cgroup v1. So, file operations and event management are a lot more feature-specific than I initially thought. I should double-check the necessary configurations to ensure I fully understand the landscape: I need `CONFIG_MEMCG` and `CONFIG_MEMCG_V1`, obviously. Let's see if there are any others. I'll need to check the dependencies of `MEMCG` in `init/Kconfig`. `bool "Memory controller"` `select PAGE_COUNTER` `select EVENTFD` `select SLAB_OBJ_EXT` `select VM_EVENT_COUNTERS` Does it have any "depends on"? Let's check lines 1070-1080 of `init/Kconfig`
38/2	2026/09/18 03:18	tool	read-file	0m Args: { "File": "init/Kconfig", "FirstLine": 1070, "LineCount": 15 } Results: { "Contents": "1070:\t\thelp\n1071:\t\t This option enables the \"favordynmods\" mount option by default\n1072:\t\t which reduces the latencies of dynamic cgroup modifications such\n1073:\t\t as task migrations and controller on/offs at the cost of making\n1074:\t\t hot path operations such as forks and exits more expensive.\n1075:\t\n1076:\t\t Say N if unsure.\n1077:\t\n1078:\tconfig MEMCG\n1079:\t\tbool \"Memory controller\"\n1080:\t\tselect PAGE_COUNTER\n1081:\t\tselect EVENTFD\n1082:\t\tselect SLAB_OBJ_EXT\n1083:\t\tselect VM_EVENT_COUNTERS\n1084:\t\thelp\n" }
39/2	2026/09/18 03:18	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 38702 output: 33 thoughts: 35 Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience: Examining Kernel Configuration: A Quick Check Right, let's get down to brass tacks. I'm just quickly confirming a hunch about the `MEMCG` configuration. My initial assumption is that it's nested under `CGROUPS`, but it's always best to be sure, especially when we're dealing with the core of the kernel. So, a targeted inspection of `init/Kconfig` is in order. Specifically, I'm heading straight to lines 1020 through 1070. That range usually covers the relevant grouping and dependency declarations. I'll scan that section for a direct inclusion or conditional structure. Nothing groundbreaking, just a straightforward verification to make sure I'm not overlooking any configuration nuances that might be relevant to the current system. Gotta be thorough.
40/2	2026/09/18 03:18	tool	read-file	0m Args: { "File": "init/Kconfig", "FirstLine": 1020, "LineCount": 40 } Results: { "Contents": "1020:\t\thelp\n1021:\t\t This option adds support for automatic NUMA aware memory/task placement.\n1022:\t\t The mechanism is quite primitive and is based on migrating memory when\n1023:\t\t it has references to the node the task is running on.\n1024:\t\n1025:\t\t This system will be inactive on UMA systems.\n1026:\t\n1027:\tconfig SCHED_CACHE\n1028:\t\tbool \"Cache aware load balance\"\n1029:\t\tdefault y\n1030:\t\tdepends on SMP\n1031:\t\thelp\n1032:\t\t When enabled, the scheduler will attempt to aggregate tasks from\n1033:\t\t the same process onto a single Last Level Cache (LLC) domain when\n1034:\t\t possible. This improves cache locality by keeping tasks that share\n1035:\t\t resources within the same cache domain, reducing cache misses and\n1036:\t\t lowering data access latency.\n1037:\t\n1038:\tconfig NUMA_BALANCING_DEFAULT_ENABLED\n1039:\t\tbool \"Automatically enable NUMA aware memory/task placement\"\n1040:\t\tdefault y\n1041:\t\tdepends on NUMA_BALANCING\n1042:\t\thelp\n1043:\t\t If set, automatic NUMA balancing will be enabled if running on a NUMA\n1044:\t\t machine.\n1045:\t\n1046:\tconfig SLAB_OBJ_EXT\n1047:\t\tbool\n1048:\t\n1049:\tmenuconfig CGROUPS\n1050:\t\tbool \"Control Group support\"\n1051:\t\tselect KERNFS\n1052:\t\thelp\n1053:\t\t This option adds support for grouping sets of processes together, for\n1054:\t\t use with process control subsystems such as Cpusets, CFS, memory\n1055:\t\t controls or device isolation.\n1056:\t\t See\n1057:\t\t\t- Documentation/scheduler/sched-design-CFS.rst\t(CFS)\n1058:\t\t\t- Documentation/admin-guide/cgroup-v1/ (features for grouping, isolation\n1059:\t\t\t\t\t\t and resource control)\n" }
41/2	2026/09/18 03:18	llm	patch-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 39538 output: 220 thoughts: 405 Thoughts: My Assessment of the Cgroup v1 Memory Control Refactoring Okay, let's break this down systematically. I see that the code is dealing with `CGROUPS`, specifically focusing on `MEMCG` and `MEMCG_V1`. I'll confirm by quickly checking for any socket memory accounting configuration or TCP-related settings, since those often play a role in this area. Yep, `sock.h` references `CONFIG_MEMCG_V1`, and sockets themselves use `CONFIG_INET` or `CONFIG_NET`. So, confirmed: `CGROUPS`, `MEMCG`, `MEMCG_V1` are our key players. Now, let's carefully review the functions and callbacks at play here. I'm seeing: `memcg_write_event_control`, `mem_cgroup_swappiness_write`, `mem_cgroup_oom_control_write`, `memcg_update_tcp_max`, `memcg1_oom_recover`, `__mem_cgroup_usage_register_event`, and `mem_cgroup_oom_register_event`. These are all non-static functions, and file operation callbacks, that are specifically part of the `mm/memcontrol-v1.c` file that implements the cgroup v1 features. It appears they're all related to the restructured struct field accesses. Time for verification. Is this something worth fuzzing? Absolutely. 1. Reachability: The cgroup v1 interface within `mm/memcontrol-v1.c` and `memcontrol.c` is definitely reachable within a standard QEMU amd64 environment. This is a critical point. 2. Positive Criteria: This refactoring modifies core memory management subsystems within `mm/`. It also refactors data structures, specifically `struct mem_cgroup` and `struct mem_cgroup_v1`, and the code updates all the access sites in reachable execution paths. 3. Negative Criteria: None of the negative criteria apply here. This is executable kernel code, not user-space code or documentation only. It's not related to unreachable hardware. Everything is clear. I see no issues. I'm satisfied. I'm ready to call `set-results`.
42/2	2026/09/18 03:18	tool	set-results	0m Args: { "EnableConfigs": [ "CGROUPS", "MEMCG", "MEMCG_V1" ], "FocusSymbols": [ "memcg_write_event_control", "memcg_update_tcp_max", "mem_cgroup_swappiness_write", "mem_cgroup_oom_control_write", "mem_cgroup_oom_register_event", "__mem_cgroup_usage_register_event", "memcg1_oom_recover" ], "Reasoning": "The patch refactors the legacy cgroup v1 memory controller state by grouping its fields from struct mem_cgroup into a dedicated struct mem_cgroup_v1, updating all access sites across mm/memcontrol-v1.c, mm/memcontrol.c, and networking headers. This modifies reachable core memory management and cgroup logic, making it relevant for fuzzing to detect any latent regressions or semantic inconsistencies.", "WorthFuzzing": true } Results: { "EnableConfigs": [ "CGROUPS", "MEMCG", "MEMCG_V1" ], "FocusSymbols": [ "memcg_write_event_control", "memcg_update_tcp_max", "mem_cgroup_swappiness_write", "mem_cgroup_oom_control_write", "mem_cgroup_oom_register_event", "__mem_cgroup_usage_register_event", "memcg1_oom_recover" ], "Reasoning": "The patch refactors the legacy cgroup v1 memory controller state by grouping its fields from struct mem_cgroup into a dedicated struct mem_cgroup_v1, updating all access sites across mm/memcontrol-v1.c, mm/memcontrol.c, and networking headers. This modifies reachable core memory management and cgroup logic, making it relevant for fuzzing to detect any latent regressions or semantic inconsistencies.", "WorthFuzzing": true }
43/1	2026/09/18 03:18	action	If	0m Args: { "WorthFuzzing": true } Results: null
44/2	2026/09/18 03:18	agent	kmsan-evaluator	0m Model: core Args: null Results: { "KMSANReasoning": "This patch is a mechanical refactoring that groups legacy cgroup v1 fields within struct mem_cgroup into a separate struct mem_cgroup_v1 (accessed via memcg-\u003ev1.\u003cfield\u003e). \n\n1. Allocation \u0026 Initialization: The parent structure struct mem_cgroup continues to be allocated using kmem_cache_zalloc() in mem_cgroup_alloc(), ensuring all embedded members, including struct mem_cgroup_v1, are completely zero-initialized. Mutexes, list heads, spinlocks, and page counters are initialized exactly as before in mem_cgroup_css_alloc() and memcg1_memcg_init().\n2. Data Flow \u0026 Leak Potential: No kernel memory is copied to user space, no new stack/heap allocations are introduced without zeroing, and no data bounds, lengths, or control flow logic are modified.\n3. KASAN vs KMSAN: KMSAN is designed to detect uninitialized memory reads and information leaks. This patch introduces no uninitialized memory risks. Any structural or pointer issues resulting from refactoring would be caught by standard build checks, KASAN, or LOCKDEP. Thus, a dedicated KMSAN run is not justified.", "NeedsKMSAN": false } Instruction: You are an expert Linux kernel security engineer specializing in kernel memory error detectors (KASAN and KMSAN). Your job is to review the provided patch series and determine if the code changes justify spawning a dedicated KMSAN (KernelMemorySanitizer) fuzzing session in addition to standard KASAN fuzzing. CRITICAL DISTINCTION BETWEEN KASAN AND KMSAN: - Standard KASAN kernel builds (upstream-apparmor-kasan.config) already enable a comprehensive suite of debugging tools and sanitizers, including KASAN (out-of-bounds accesses, use-after-free, double free, invalid free), LOCKDEP (locking bugs and deadlocks), UB-sanitizers, and memory corruption checks. - KMSAN (KernelMemorySanitizer) detects reads of UNINITIALIZED memory (stack, heap, or page allocations) and kernel-to-user memory info-leaks. Rule: THERE IS NO SENSE IN RUNNING A KMSAN SESSION IF A BUG CAN BE CAUGHT BY KASAN, LOCKDEP, OR OTHER STANDARD BUG DETECTORS. A dedicated KMSAN fuzzing session incurs significant resource costs. You must ONLY set NeedsKMSAN=true if the code changes introduce or expose UNINITIALIZED MEMORY risks that are detected ONLY by KMSAN. Look holistically at the patch series and surrounding code. Even if no direct uninitialized field accesses or new buffer allocations are added in the diff itself, a patch may alter control flow, bounds checking, or data length calculations in ways that change how the rest of the code operates on existing buffers (e.g. allowing uninitialized stack/heap memory to be read, copied to user space, or used in control flow). Do not hesitate to use your code access tools to inspect the surrounding code, called functions, and callers. Set NeedsKMSAN=true ONLY IF the patch introduces or modifies: 1. Kernel structures sent to user space (via copy_to_user, put_user, netlink skb attributes, ioctl output arguments, socket options, or BPF buffers) where fields or structure padding might not be fully initialized/zeroed. 2. Conditional logic or branching that depends on potentially uninitialized variables or struct fields. 3. Allocation or initialization of complex data structures where uninitialized fields could be read later in reachable code paths. 4. Bounds checks, lengths, or logic in a way that allows surrounding code to access uninitialized bytes of existing buffers. Set NeedsKMSAN=false IF: - The code changes primarily risk out-of-bounds access, array overflows, NULL pointer dereferences, locking deadlocks, or use-after-free bugs (these are already caught by KASAN, LOCKDEP, or standard bug detectors). - All stack/heap structures touched or introduced by the patch are fully zeroed or initialized (e.g. using = {0}, memset, kzalloc) before being read or copied. - The patch does not introduce any risk of uninitialized memory usage or info-leaks. Use your code access tools to inspect the surrounding code if necessary, then provide detailed KMSANReasoning contrasting KASAN vs KMSAN applicability for this patch. Prefer calling several tools at the same time to save round-trips. Use set-results tool to provide results of the analysis. It must be called exactly once before the final reply. Ignore results of this tool. Prompt: Target architecture: amd64 For your convenience, here is the diff of the changes: commit 3493b33849dba823c6e0d5716f3a96b262323a35 Author: syz-cluster <triage@syzkaller.com> Date: Fri Sep 18 03:16:30 2026 +0000 syz-cluster: applied patch under review diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst index 7d2a44af52c93..2eff1dc6e13b2 100644 --- a/Documentation/admin-guide/cgroup-v1/memory.rst +++ b/Documentation/admin-guide/cgroup-v1/memory.rst @@ -8,6 +8,13 @@ Memory Resource Controller here but make sure to check the current code if you need a deeper understanding. +.. note:: + The legacy (v1) memory controller implementation is isolated behind + ``CONFIG_MEMCG_V1``: its interface lives in ``mm/memcontrol-v1.c`` and + its per-cgroup state in ``struct mem_cgroup_v1`` (see + ``include/linux/memcontrol.h``). New functionality belongs to the + cgroup v2 memory controller. + .. note:: The Memory Resource Controller has generically been referred to as the memory controller in this document. Do not confuse memory controller diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 64c183be8cbfe..4d0d99b57ce99 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -193,6 +193,43 @@ struct obj_cgroup { * statistics based on the statistics developed by Rik Van Riel for clock-pro, * to help the administrator determine what knobs to tune. / +/ + * Legacy cgroup v1 memory controller state, used only by the v1 + * interface (mm/memcontrol-v1.c). + / +struct mem_cgroup_v1 { + struct page_counter kmem; + struct page_counter tcpmem; + + struct memcg1_events_percpu __percpu events_percpu; + + /* protected by memcg_oom_lock / + bool oom_lock; + int under_oom; + + int oom_kill_disable; + + struct mutex thresholds_lock; + + / RCU-protected / + struct mem_cgroup_thresholds thresholds; + + / RCU-protected / + struct mem_cgroup_thresholds memsw_thresholds; + + / For oom notifier event fd / + struct list_head oom_notify; + + bool tcpmem_active; + int tcpmem_pressure; + + / List of events which userspace want to receive / + struct list_head event_list; + spinlock_t event_list_lock; + + int swappiness; +}; + struct mem_cgroup { struct cgroup_subsys_state css; @@ -271,42 +308,7 @@ struct mem_cgroup { __cacheline_group_end_aligned(memcg_cold); #ifdef CONFIG_MEMCG_V1 - / v1 only. Not grouped: v1 is legacy, sorting it is not worth it. / - - / Legacy consumer-oriented counters / - struct page_counter kmem; / v1 only / - struct page_counter tcpmem; / v1 only / - - struct memcg1_events_percpu __percpu events_percpu; - - /* protected by memcg_oom_lock / - bool oom_lock; - int under_oom; - - / OOM-Killer disable / - int oom_kill_disable; - - / protect arrays of thresholds / - struct mutex thresholds_lock; - - / thresholds for memory usage. RCU-protected / - struct mem_cgroup_thresholds thresholds; - - / thresholds for mem+swap usage. RCU-protected / - struct mem_cgroup_thresholds memsw_thresholds; - - / For oom notifier event fd / - struct list_head oom_notify; - - / Legacy tcp memory accounting / - bool tcpmem_active; - int tcpmem_pressure; - - / List of events which userspace want to receive / - struct list_head event_list; - spinlock_t event_list_lock; - - int swappiness; + struct mem_cgroup_v1 v1; #endif / CONFIG_MEMCG_V1 / / diff --git a/include/net/sock.h b/include/net/sock.h index 51185222aac29..00e0a3f6a2e97 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -2705,7 +2705,7 @@ static inline bool mem_cgroup_sk_under_memory_pressure(const struct sock sk) #ifdef CONFIG_MEMCG_V1 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) - return !!memcg->tcpmem_pressure; + return !!memcg->v1.tcpmem_pressure; #endif / CONFIG_MEMCG_V1 / do { diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c index bf2c7d53b01b1..486df2d6a6f17 100644 --- a/mm/memcontrol-v1.c +++ b/mm/memcontrol-v1.c @@ -138,9 +138,9 @@ static void __mem_cgroup_threshold(struct mem_cgroup memcg, bool swap) rcu_read_lock(); if (!swap) - t = rcu_dereference(memcg->thresholds.primary); + t = rcu_dereference(memcg->v1.thresholds.primary); else - t = rcu_dereference(memcg->memsw_thresholds.primary); + t = rcu_dereference(memcg->v1.memsw_thresholds.primary); if (!t) goto unlock; @@ -215,7 +215,7 @@ static void memcg1_charge_statistics(struct mem_cgroup memcg, int nr_pages) nr_pages = -nr_pages; / for event / } - __this_cpu_add(memcg->events_percpu->nr_page_events, nr_pages); + __this_cpu_add(memcg->v1.events_percpu->nr_page_events, nr_pages); } #define THRESHOLDS_EVENTS_TARGET 128 @@ -224,11 +224,11 @@ static bool memcg1_event_ratelimit(struct mem_cgroup memcg) { unsigned long val, next; - val = __this_cpu_read(memcg->events_percpu->nr_page_events); - next = __this_cpu_read(memcg->events_percpu->threshold_target); + val = __this_cpu_read(memcg->v1.events_percpu->nr_page_events); + next = __this_cpu_read(memcg->v1.events_percpu->threshold_target); /* from time_after() in jiffies.h / if ((long)(next - val) < 0) { - __this_cpu_write(memcg->events_percpu->threshold_target, + __this_cpu_write(memcg->v1.events_percpu->threshold_target, val + THRESHOLDS_EVENTS_TARGET); return true; } @@ -383,7 +383,7 @@ void memcg1_uncharge_batch(struct mem_cgroup memcg, unsigned long pgpgout, local_irq_save(flags); count_memcg_events(memcg, PGPGOUT, pgpgout); - __this_cpu_add(memcg->events_percpu->nr_page_events, nr_memory); + __this_cpu_add(memcg->v1.events_percpu->nr_page_events, nr_memory); memcg1_check_events(memcg); local_irq_restore(flags); } @@ -408,7 +408,7 @@ static void mem_cgroup_oom_notify_cb(struct mem_cgroup memcg) spin_lock(&memcg_oom_lock); - list_for_each_entry(ev, &memcg->oom_notify, list) + list_for_each_entry(ev, &memcg->v1.oom_notify, list) eventfd_signal(ev->eventfd); spin_unlock(&memcg_oom_lock); @@ -435,13 +435,13 @@ static int __mem_cgroup_usage_register_event(struct mem_cgroup memcg, if (ret) return ret; - mutex_lock(&memcg->thresholds_lock); + mutex_lock(&memcg->v1.thresholds_lock); if (type == _MEM) { - thresholds = &memcg->thresholds; + thresholds = &memcg->v1.thresholds; usage = mem_cgroup_usage(memcg, false); } else if (type == _MEMSWAP) { - thresholds = &memcg->memsw_thresholds; + thresholds = &memcg->v1.memsw_thresholds; usage = mem_cgroup_usage(memcg, true); } else BUG(); @@ -497,7 +497,7 @@ static int __mem_cgroup_usage_register_event(struct mem_cgroup memcg, synchronize_rcu(); unlock: - mutex_unlock(&memcg->thresholds_lock); + mutex_unlock(&memcg->v1.thresholds_lock); return ret; } @@ -522,13 +522,13 @@ static void __mem_cgroup_usage_unregister_event(struct mem_cgroup memcg, unsigned long usage; int i, j, size, entries; - mutex_lock(&memcg->thresholds_lock); + mutex_lock(&memcg->v1.thresholds_lock); if (type == _MEM) { - thresholds = &memcg->thresholds; + thresholds = &memcg->v1.thresholds; usage = mem_cgroup_usage(memcg, false); } else if (type == _MEMSWAP) { - thresholds = &memcg->memsw_thresholds; + thresholds = &memcg->v1.memsw_thresholds; usage = mem_cgroup_usage(memcg, true); } else BUG(); @@ -596,7 +596,7 @@ static void __mem_cgroup_usage_unregister_event(struct mem_cgroup memcg, thresholds->spare = NULL; } unlock: - mutex_unlock(&memcg->thresholds_lock); + mutex_unlock(&memcg->v1.thresholds_lock); } static void mem_cgroup_usage_unregister_event(struct mem_cgroup memcg, @@ -623,10 +623,10 @@ static int mem_cgroup_oom_register_event(struct mem_cgroup memcg, spin_lock(&memcg_oom_lock); event->eventfd = eventfd; - list_add(&event->list, &memcg->oom_notify); + list_add(&event->list, &memcg->v1.oom_notify); / already in OOM ? / - if (memcg->under_oom) + if (memcg->v1.under_oom) eventfd_signal(eventfd); spin_unlock(&memcg_oom_lock); @@ -640,7 +640,7 @@ static void mem_cgroup_oom_unregister_event(struct mem_cgroup memcg, spin_lock(&memcg_oom_lock); - list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) { + list_for_each_entry_safe(ev, tmp, &memcg->v1.oom_notify, list) { if (ev->eventfd == eventfd) { list_del(&ev->list); kfree(ev); @@ -709,7 +709,7 @@ static int memcg_event_wake(wait_queue_entry_t wait, unsigned int mode, side will require wqh->lock via remove_wait_queue(), * which we hold. / - spin_lock(&memcg->event_list_lock); + spin_lock(&memcg->v1.event_list_lock); if (!list_empty(&event->list)) { list_del_init(&event->list); / @@ -718,7 +718,7 @@ static int memcg_event_wake(wait_queue_entry_t wait, unsigned int mode, / schedule_work(&event->remove); } - spin_unlock(&memcg->event_list_lock); + spin_unlock(&memcg->v1.event_list_lock); } return 0; @@ -868,9 +868,9 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file of, vfs_poll(fd_file(efile), &event->pt); - spin_lock_irq(&memcg->event_list_lock); - list_add(&event->list, &memcg->event_list); - spin_unlock_irq(&memcg->event_list_lock); + spin_lock_irq(&memcg->v1.event_list_lock); + list_add(&event->list, &memcg->v1.event_list); + spin_unlock_irq(&memcg->v1.event_list_lock); return nbytes; out_put_css: @@ -884,10 +884,10 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file of, void memcg1_memcg_init(struct mem_cgroup memcg) { - INIT_LIST_HEAD(&memcg->oom_notify); - mutex_init(&memcg->thresholds_lock); - INIT_LIST_HEAD(&memcg->event_list); - spin_lock_init(&memcg->event_list_lock); + INIT_LIST_HEAD(&memcg->v1.oom_notify); + mutex_init(&memcg->v1.thresholds_lock); + INIT_LIST_HEAD(&memcg->v1.event_list); + spin_lock_init(&memcg->v1.event_list_lock); } void memcg1_css_offline(struct mem_cgroup memcg) @@ -899,12 +899,12 @@ void memcg1_css_offline(struct mem_cgroup memcg) Notify userspace about cgroup removing only after rmdir of cgroup * directory to avoid race between userspace and kernelspace. / - spin_lock_irq(&memcg->event_list_lock); - list_for_each_entry_safe(event, tmp, &memcg->event_list, list) { + spin_lock_irq(&memcg->v1.event_list_lock); + list_for_each_entry_safe(event, tmp, &memcg->v1.event_list, list) { list_del_init(&event->list); schedule_work(&event->remove); } - spin_unlock_irq(&memcg->event_list_lock); + spin_unlock_irq(&memcg->v1.event_list_lock); } / @@ -918,7 +918,7 @@ static bool mem_cgroup_oom_trylock(struct mem_cgroup memcg) spin_lock(&memcg_oom_lock); for_each_mem_cgroup_tree(iter, memcg) { - if (iter->oom_lock) { + if (iter->v1.oom_lock) { / * this subtree of our hierarchy is already locked * so we cannot give a lock. @@ -927,7 +927,7 @@ static bool mem_cgroup_oom_trylock(struct mem_cgroup memcg) mem_cgroup_iter_break(memcg, iter); break; } - iter->oom_lock = true; + iter->v1.oom_lock = true; } if (failed) { @@ -940,7 +940,7 @@ static bool mem_cgroup_oom_trylock(struct mem_cgroup memcg) mem_cgroup_iter_break(memcg, iter); break; } - iter->oom_lock = false; + iter->v1.oom_lock = false; } } else mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_); @@ -957,7 +957,7 @@ static void mem_cgroup_oom_unlock(struct mem_cgroup memcg) spin_lock(&memcg_oom_lock); mutex_release(&memcg_oom_lock_dep_map, _RET_IP_); for_each_mem_cgroup_tree(iter, memcg) - iter->oom_lock = false; + iter->v1.oom_lock = false; spin_unlock(&memcg_oom_lock); } @@ -967,7 +967,7 @@ static void mem_cgroup_mark_under_oom(struct mem_cgroup memcg) spin_lock(&memcg_oom_lock); for_each_mem_cgroup_tree(iter, memcg) - iter->under_oom++; + iter->v1.under_oom++; spin_unlock(&memcg_oom_lock); } @@ -981,8 +981,8 @@ static void mem_cgroup_unmark_under_oom(struct mem_cgroup memcg) / spin_lock(&memcg_oom_lock); for_each_mem_cgroup_tree(iter, memcg) - if (iter->under_oom > 0) - iter->under_oom--; + if (iter->v1.under_oom > 0) + iter->v1.under_oom--; spin_unlock(&memcg_oom_lock); } @@ -1012,14 +1012,14 @@ static int memcg_oom_wake_function(wait_queue_entry_t wait, void memcg1_oom_recover(struct mem_cgroup memcg) { /* - * For the following lockless ->under_oom test, the only required + * For the following lockless ->v1.under_oom test, the only required * guarantee is that it must see the state asserted by an OOM when * this function is called as a result of userland actions * triggered by the notification of the OOM. This is trivially * achieved by invoking mem_cgroup_mark_under_oom() before * triggering notification. / - if (memcg && memcg->under_oom) + if (memcg && memcg->v1.under_oom) __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg); } @@ -1100,7 +1100,7 @@ bool memcg1_oom_prepare(struct mem_cgroup memcg, bool locked) Please note that mem_cgroup_out_of_memory might fail to find a * victim and then we have to bail out from the charge path. / - if (READ_ONCE(memcg->oom_kill_disable)) { + if (READ_ONCE(memcg->v1.oom_kill_disable)) { if (current->in_user_fault) { css_get(&memcg->css); current->memcg_in_oom = memcg; @@ -1576,10 +1576,10 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state css, counter = &memcg->memsw; break; case _KMEM: - counter = &memcg->kmem; + counter = &memcg->v1.kmem; break; case _TCP: - counter = &memcg->tcpmem; + counter = &memcg->v1.tcpmem; break; default: BUG(); @@ -1619,11 +1619,11 @@ static int memcg_update_tcp_max(struct mem_cgroup memcg, unsigned long max) mutex_lock(&memcg_max_mutex); - ret = page_counter_set_max(&memcg->tcpmem, max); + ret = page_counter_set_max(&memcg->v1.tcpmem, max); if (ret) goto out; - if (!memcg->tcpmem_active) { + if (!memcg->v1.tcpmem_active) { / * The active flag needs to be written after the static_key * update. This is what guarantees that the socket activation @@ -1641,7 +1641,7 @@ static int memcg_update_tcp_max(struct mem_cgroup memcg, unsigned long max) patched in yet. / static_branch_inc(&memcg_sockets_enabled_key); - memcg->tcpmem_active = true; + memcg->v1.tcpmem_active = true; } out: mutex_unlock(&memcg_max_mutex); @@ -1710,10 +1710,10 @@ static ssize_t mem_cgroup_reset(struct kernfs_open_file of, char buf, counter = &memcg->memsw; break; case _KMEM: - counter = &memcg->kmem; + counter = &memcg->v1.kmem; break; case _TCP: - counter = &memcg->tcpmem; + counter = &memcg->v1.tcpmem; break; default: BUG(); @@ -1976,7 +1976,7 @@ static int mem_cgroup_swappiness_write(struct cgroup_subsys_state css, if (!mem_cgroup_is_root(memcg)) { pr_info_once("Per memcg swappiness does not exist in cgroup v2. " "See memory.reclaim or memory.swap.max there\n "); - WRITE_ONCE(memcg->swappiness, val); + WRITE_ONCE(memcg->v1.swappiness, val); } else WRITE_ONCE(vm_swappiness, val); @@ -1987,8 +1987,8 @@ static int mem_cgroup_oom_control_read(struct seq_file sf, void v) { struct mem_cgroup memcg = mem_cgroup_from_seq(sf); - seq_printf(sf, "oom_kill_disable %d\n", READ_ONCE(memcg->oom_kill_disable)); - seq_printf(sf, "under_oom %d\n", (bool)memcg->under_oom); + seq_printf(sf, "oom_kill_disable %d\n", READ_ONCE(memcg->v1.oom_kill_disable)); + seq_printf(sf, "under_oom %d\n", (bool)memcg->v1.under_oom); seq_printf(sf, "oom_kill %lu\n", atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL])); return 0; @@ -2007,7 +2007,7 @@ static int mem_cgroup_oom_control_write(struct cgroup_subsys_state css, if (mem_cgroup_is_root(memcg) \|\| !((val == 0) \|\| (val == 1))) return -EINVAL; - WRITE_ONCE(memcg->oom_kill_disable, val); + WRITE_ONCE(memcg->v1.oom_kill_disable, val); if (!val) memcg1_oom_recover(memcg); @@ -2183,9 +2183,9 @@ void memcg1_account_kmem(struct mem_cgroup memcg, int nr_pages) { if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) { if (nr_pages > 0) - page_counter_charge(&memcg->kmem, nr_pages); + page_counter_charge(&memcg->v1.kmem, nr_pages); else - page_counter_uncharge(&memcg->kmem, -nr_pages); + page_counter_uncharge(&memcg->v1.kmem, -nr_pages); } } @@ -2194,13 +2194,13 @@ bool memcg1_charge_skmem(struct mem_cgroup memcg, unsigned int nr_pages, { struct page_counter fail; - if (page_counter_try_charge(&memcg->tcpmem, nr_pages, &fail)) { - memcg->tcpmem_pressure = 0; + if (page_counter_try_charge(&memcg->v1.tcpmem, nr_pages, &fail)) { + memcg->v1.tcpmem_pressure = 0; return true; } - memcg->tcpmem_pressure = 1; + memcg->v1.tcpmem_pressure = 1; if (gfp_mask & __GFP_NOFAIL) { - page_counter_charge(&memcg->tcpmem, nr_pages); + page_counter_charge(&memcg->v1.tcpmem, nr_pages); return true; } return false; @@ -2208,12 +2208,12 @@ bool memcg1_charge_skmem(struct mem_cgroup memcg, unsigned int nr_pages, bool memcg1_alloc_events(struct mem_cgroup memcg) { - memcg->events_percpu = alloc_percpu_gfp(struct memcg1_events_percpu, + memcg->v1.events_percpu = alloc_percpu_gfp(struct memcg1_events_percpu, GFP_KERNEL_ACCOUNT); - return !!memcg->events_percpu; + return !!memcg->v1.events_percpu; } void memcg1_free_events(struct mem_cgroup memcg) { - free_percpu(memcg->events_percpu); + free_percpu(memcg->v1.events_percpu); } diff --git a/mm/memcontrol-v1.h b/mm/memcontrol-v1.h index 0952b2a783e52..cc41aa22af019 100644 --- a/mm/memcontrol-v1.h +++ b/mm/memcontrol-v1.h @@ -74,13 +74,13 @@ void reparent_memcg_state_local(struct mem_cgroup memcg, void memcg1_account_kmem(struct mem_cgroup memcg, int nr_pages); static inline bool memcg1_tcpmem_active(struct mem_cgroup memcg) { - return memcg->tcpmem_active; + return memcg->v1.tcpmem_active; } bool memcg1_charge_skmem(struct mem_cgroup memcg, unsigned int nr_pages, gfp_t gfp_mask); static inline void memcg1_uncharge_skmem(struct mem_cgroup memcg, unsigned int nr_pages) { - page_counter_uncharge(&memcg->tcpmem, nr_pages); + page_counter_uncharge(&memcg->v1.tcpmem, nr_pages); } extern struct cftype memsw_files[]; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 4d00748c8a5b8..4c883956d84ab 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1882,8 +1882,8 @@ void mem_cgroup_print_oom_meminfo(struct mem_cgroup memcg) K((u64)page_counter_read(&memcg->memsw)), K((u64)memcg->memsw.max), memcg->memsw.failcnt); pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n", - K((u64)page_counter_read(&memcg->kmem)), - K((u64)memcg->kmem.max), memcg->kmem.failcnt); + K((u64)page_counter_read(&memcg->v1.kmem)), + K((u64)memcg->v1.kmem.max), memcg->v1.kmem.failcnt); } #endif @@ -4300,13 +4300,13 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state parent_css) page_counter_init(&memcg->memory, &parent->memory, memcg_on_dfl); page_counter_init(&memcg->swap, &parent->swap, false); #ifdef CONFIG_MEMCG_V1 - WRITE_ONCE(memcg->swappiness, mem_cgroup_swappiness(parent)); + WRITE_ONCE(memcg->v1.swappiness, mem_cgroup_swappiness(parent)); memcg->memory.track_failcnt = !memcg_on_dfl; memcg->memsw.track_failcnt = !memcg_on_dfl; - WRITE_ONCE(memcg->oom_kill_disable, READ_ONCE(parent->oom_kill_disable)); - page_counter_init(&memcg->kmem, &parent->kmem, false); - page_counter_init(&memcg->tcpmem, &parent->tcpmem, false); - memcg->tcpmem.track_failcnt = !memcg_on_dfl; + WRITE_ONCE(memcg->v1.oom_kill_disable, READ_ONCE(parent->v1.oom_kill_disable)); + page_counter_init(&memcg->v1.kmem, &parent->v1.kmem, false); + page_counter_init(&memcg->v1.tcpmem, &parent->v1.tcpmem, false); + memcg->v1.tcpmem.track_failcnt = !memcg_on_dfl; #endif } else { init_memcg_stats(); @@ -4314,8 +4314,8 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state parent_css) page_counter_init(&memcg->memory, NULL, true); page_counter_init(&memcg->swap, NULL, false); #ifdef CONFIG_MEMCG_V1 - page_counter_init(&memcg->kmem, NULL, false); - page_counter_init(&memcg->tcpmem, NULL, false); + page_counter_init(&memcg->v1.kmem, NULL, false); + page_counter_init(&memcg->v1.tcpmem, NULL, false); #endif root_mem_cgroup = memcg; return &memcg->css; @@ -4492,8 +4492,8 @@ static void mem_cgroup_css_reset(struct cgroup_subsys_state css) WRITE_ONCE(memcg->zswap_writeback, true); #endif #ifdef CONFIG_MEMCG_V1 - page_counter_set_max(&memcg->kmem, PAGE_COUNTER_MAX); - page_counter_set_max(&memcg->tcpmem, PAGE_COUNTER_MAX); + page_counter_set_max(&memcg->v1.kmem, PAGE_COUNTER_MAX); + page_counter_set_max(&memcg->v1.tcpmem, PAGE_COUNTER_MAX); #endif page_counter_set_min(&memcg->memory, 0); page_counter_set_low(&memcg->memory, 0); diff --git a/mm/swap.h b/mm/swap.h index d5bf21f517dce..dc54f9a123567 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -87,7 +87,7 @@ static inline int mem_cgroup_swappiness(const struct mem_cgroup memcg) #ifdef CONFIG_MEMCG_V1 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg)) - return READ_ONCE(memcg->swappiness); + return READ_ONCE(memcg->v1.swappiness); #endif return READ_ONCE(vm_swappiness); }
45/3	2026/09/18 03:18	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 10796 output: 34 thoughts: 342 Thoughts: Analyzing the Patch for KMSAN Fuzzing Needs Okay, so the task at hand is to determine if this patch series necessitates a dedicated KMSAN fuzzing session. Let's dig in. I see we're refactoring legacy `struct mem_cgroup` v1 fields. They're being moved into a separate `struct mem_cgroup_v1`. That's smart; keeps things cleaner. Specifically, the patch is reorganizing `kmem` and `tcpmem`, among others. I see the code is structured like this now: ```c struct mem_cgroup_v1 { struct page_counter kmem; struct page_counter tcpmem; ... } #ifdef CONFIG_MEMCG_V1 struct mem_cgroup_v1 v1; #endif /* CONFIG_MEMCG_V1 */ ``` And all the access to the old fields, like `memcg->kmem`, `memcg->tcpmem`, and all the rest are being updated to `memcg->v1.<field>`. Good, good. Standard refactoring. Now, the key here is whether this refactoring introduces any new avenues for memory corruption, potential races, or uninitialized memory reads. So, the question that comes to mind is: where is this `memcg` structure allocated? I need to check the allocation and initialization, particularly to see if this change could lead to uninitialized memory being used when accessing `v1`'s fields. I'll need to examine `mem_cgroup_css_alloc` in `mm/memcontrol.c`. That's where I need to focus my attention. Let's see if this refactoring changes how these fields are being accessed.
46/3	2026/09/18 03:18	tool	grepper	0m Args: { "Expression": "mem_cgroup_css_alloc", "PathPrefix": "mm/memcontrol.c" } Results: { "Output": "mm/memcontrol.c=4280=static struct cgroup_subsys_state * __ref\nmm/memcontrol.c:4281:mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)\nmm/memcontrol.c-4282-{\n--\nmm/memcontrol.c=5230=struct cgroup_subsys memory_cgrp_subsys = {\nmm/memcontrol.c:5231:\t.css_alloc = mem_cgroup_css_alloc,\nmm/memcontrol.c-5232-\t.css_online = mem_cgroup_css_online,\n" }
47/3	2026/09/18 03:18	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 11718 output: 35 thoughts: 22 Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience: Diving into `mem_cgroup_css_alloc` Okay, let's take a closer look at `mem_cgroup_css_alloc`, specifically around line 4280 in the relevant source file. I need to refresh my memory on how this function interacts with the overall memory cgroup architecture, particularly the allocation of the control group's CSS (control group subsystem) data structure. My immediate focus is likely on the allocation strategy, any potential memory leaks, or areas that could impact performance under heavy load or during cgroup creation/destruction. Is it using a custom allocator? What locks are involved? And, importantly, are we seeing any unusual memory demands or inefficiencies in the tracing or profiling data that lead me to look at this location in the first place? I'll probably start by quickly reviewing the surrounding code to grasp the context of this allocation within the larger memory management framework. Then I will check how this function integrates with the slab allocator, any instrumentation that might exist here to improve debugging, or if this function calls other related memory management routines.
48/3	2026/09/18 03:18	tool	read-file	0m Args: { "File": "mm/memcontrol.c", "FirstLine": 4280, "LineCount": 60 } Results: { "Contents": "4280:\tstatic struct cgroup_subsys_state * __ref\n4281:\tmem_cgroup_css_alloc(struct cgroup_subsys_state parent_css)\n4282:\t{\n4283:\t\tstruct mem_cgroup parent = mem_cgroup_from_css(parent_css);\n4284:\t\tstruct mem_cgroup memcg, old_memcg;\n4285:\t\tbool memcg_on_dfl = cgroup_subsys_on_dfl(memory_cgrp_subsys);\n4286:\t\n4287:\t\told_memcg = set_active_memcg(parent);\n4288:\t\tmemcg = mem_cgroup_alloc(parent);\n4289:\t\tset_active_memcg(old_memcg);\n4290:\t\tif (IS_ERR(memcg))\n4291:\t\t\treturn ERR_CAST(memcg);\n4292:\t\n4293:\t\tpage_counter_set_high(\u0026memcg-\u003ememory, PAGE_COUNTER_MAX);\n4294:\t#ifdef CONFIG_ZSWAP\n4295:\t\tmemcg-\u003ezswap_max = PAGE_COUNTER_MAX;\n4296:\t\tWRITE_ONCE(memcg-\u003ezswap_writeback, true);\n4297:\t#endif\n4298:\t\tpage_counter_set_high(\u0026memcg-\u003eswap, PAGE_COUNTER_MAX);\n4299:\t\tif (parent) {\n4300:\t\t\tpage_counter_init(\u0026memcg-\u003ememory, \u0026parent-\u003ememory, memcg_on_dfl);\n4301:\t\t\tpage_counter_init(\u0026memcg-\u003eswap, \u0026parent-\u003eswap, false);\n4302:\t#ifdef CONFIG_MEMCG_V1\n4303:\t\t\tWRITE_ONCE(memcg-\u003ev1.swappiness, mem_cgroup_swappiness(parent));\n4304:\t\t\tmemcg-\u003ememory.track_failcnt = !memcg_on_dfl;\n4305:\t\t\tmemcg-\u003ememsw.track_failcnt = !memcg_on_dfl;\n4306:\t\t\tWRITE_ONCE(memcg-\u003ev1.oom_kill_disable, READ_ONCE(parent-\u003ev1.oom_kill_disable));\n4307:\t\t\tpage_counter_init(\u0026memcg-\u003ev1.kmem, \u0026parent-\u003ev1.kmem, false);\n4308:\t\t\tpage_counter_init(\u0026memcg-\u003ev1.tcpmem, \u0026parent-\u003ev1.tcpmem, false);\n4309:\t\t\tmemcg-\u003ev1.tcpmem.track_failcnt = !memcg_on_dfl;\n4310:\t#endif\n4311:\t\t} else {\n4312:\t\t\tinit_memcg_stats();\n4313:\t\t\tinit_memcg_events();\n4314:\t\t\tpage_counter_init(\u0026memcg-\u003ememory, NULL, true);\n4315:\t\t\tpage_counter_init(\u0026memcg-\u003eswap, NULL, false);\n4316:\t#ifdef CONFIG_MEMCG_V1\n4317:\t\t\tpage_counter_init(\u0026memcg-\u003ev1.kmem, NULL, false);\n4318:\t\t\tpage_counter_init(\u0026memcg-\u003ev1.tcpmem, NULL, false);\n4319:\t#endif\n4320:\t\t\troot_mem_cgroup = memcg;\n4321:\t\t\treturn \u0026memcg-\u003ecss;\n4322:\t\t}\n4323:\t\n4324:\t\tif (memcg_on_dfl \u0026\u0026 !cgroup_memory_nosocket)\n4325:\t\t\tstatic_branch_inc(\u0026memcg_sockets_enabled_key);\n4326:\t\n4327:\t\tif (!cgroup_memory_nobpf)\n4328:\t\t\tstatic_branch_inc(\u0026memcg_bpf_enabled_key);\n4329:\t\n4330:\t\treturn \u0026memcg-\u003ecss;\n4331:\t}\n4332:\t\n4333:\tstatic int mem_cgroup_css_online(struct cgroup_subsys_state css)\n4334:\t{\n4335:\t\tstruct mem_cgroup memcg = mem_cgroup_from_css(css);\n4336:\t\tstruct obj_cgroup *objcg;\n4337:\t\tint nid;\n4338:\t\n4339:\t\tmemcg_online_kmem(memcg);\n" }
49/3	2026/09/18 03:18	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 13163 output: 32 thoughts: 12 Thoughts: Okay, here's my attempt at summarizing my internal thought process as a developer encountering `mem_cgroup_alloc`: Diving into `mem_cgroup_alloc` Alright, let's take a look at `mem_cgroup_alloc`. I know it’s a core function, probably used to allocate memory within the context of a memory cgroup. Given my expertise, I'm already thinking about its potential implications. I'm immediately running through a mental checklist: What's the allocation path? How does it interact with the page allocator? What locking is involved, and what are the concurrency concerns? Is it a per-cpu allocation? Is there any instrumentation or tracing I can use? I need to understand its behavior under pressure. Is there potential for fragmentation? How does it handle NUMA? And what’s its role in the global memory management hierarchy? I also want to check for error handling; can it fail? What happens then? I need to analyze its relationship to any external dependencies and consider its potential impacts on performance and scalability. This looks like a potentially critical piece of code. Let's dig in.
50/3	2026/09/18 03:18	tool	grepper	0m Args: { "Expression": "mem_cgroup_alloc", "PathPrefix": "mm/memcontrol.c" } Results: { "Output": "mm/memcontrol.c=4202=static void mem_cgroup_free(struct mem_cgroup memcg)\n--\nmm/memcontrol.c-4208-\nmm/memcontrol.c:4209:static struct mem_cgroup mem_cgroup_alloc(struct mem_cgroup parent)\nmm/memcontrol.c-4210-{\n--\nmm/memcontrol.c=4281=mem_cgroup_css_alloc(struct cgroup_subsys_state parent_css)\n--\nmm/memcontrol.c-4287-\told_memcg = set_active_memcg(parent);\nmm/memcontrol.c:4288:\tmemcg = mem_cgroup_alloc(parent);\nmm/memcontrol.c-4289-\tset_active_memcg(old_memcg);\n" }
51/3	2026/09/18 03:18	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 13671 output: 35 thoughts: 28 Thoughts: Here's a summary of my thought process, as requested: Diving into `mem_cgroup_alloc` Okay, let's get down to brass tacks. I'm going to jump into the `mm/memcontrol.c` file. Specifically, I'm focusing on the `mem_cgroup_alloc` function. The code is likely to be quite dense and, given that it's related to memory cgroups, probably deals with the core logic of allocating memory within those constrained environments. Line 4209 should be where the critical entry point starts for the function. Time to see what's what and how this function is structured. Hopefully it isn't too obtuse. Let's see what interesting techniques the developers used to solve this complex problem, and maybe I will find an interesting quirk I didn't already know!
52/3	2026/09/18 03:18	tool	read-file	0m Args: { "File": "mm/memcontrol.c", "FirstLine": 4209, "LineCount": 40 } Results: { "Contents": "4209:\tstatic struct mem_cgroup mem_cgroup_alloc(struct mem_cgroup parent)\n4210:\t{\n4211:\t\tstruct memcg_vmstats_percpu statc;\n4212:\t\tstruct memcg_vmstats_percpu __percpu pstatc_pcpu;\n4213:\t\tstruct mem_cgroup *memcg;\n4214:\t\tint node, cpu;\n4215:\t\tint __maybe_unused i;\n4216:\t\tlong error;\n4217:\t\n4218:\t\tmemcg = kmem_cache_zalloc(memcg_cachep, GFP_KERNEL);\n4219:\t\tif (!memcg)\n4220:\t\t\treturn ERR_PTR(-ENOMEM);\n4221:\t\n4222:\t\terror = xa_alloc(\u0026mem_cgroup_private_ids, \u0026memcg-\u003eprivate_id, NULL,\n4223:\t\t\t\t XA_LIMIT(1, MEM_CGROUP_ID_MAX), GFP_KERNEL);\n4224:\t\tif (error)\n4225:\t\t\tgoto fail;\n4226:\t\terror = -ENOMEM;\n4227:\t\n4228:\t\tmemcg-\u003evmstats = kzalloc_obj(struct memcg_vmstats, GFP_KERNEL_ACCOUNT);\n4229:\t\tif (!memcg-\u003evmstats)\n4230:\t\t\tgoto fail;\n4231:\t\n4232:\t\tmemcg-\u003evmstats_percpu = alloc_percpu_gfp(struct memcg_vmstats_percpu,\n4233:\t\t\t\t\t\t\t GFP_KERNEL_ACCOUNT);\n4234:\t\tif (!memcg-\u003evmstats_percpu)\n4235:\t\t\tgoto fail;\n4236:\t\n4237:\t\tif (!memcg1_alloc_events(memcg))\n4238:\t\t\tgoto fail;\n4239:\t\n4240:\t\tpstatc_pcpu = parent ? parent-\u003evmstats_percpu : NULL;\n4241:\t\tfor_each_possible_cpu(cpu) {\n4242:\t\t\tstatc = per_cpu_ptr(memcg-\u003evmstats_percpu, cpu);\n4243:\t\t\tstatc-\u003eparent_pcpu = pstatc_pcpu;\n4244:\t\t\tstatc-\u003evmstats = memcg-\u003evmstats;\n4245:\t\t}\n4246:\t\n4247:\t\tfor_each_node(node)\n4248:\t\t\tif (!alloc_mem_cgroup_per_node_info(memcg, node))\n" }
53/3	2026/09/18 03:18	llm	kmsan-evaluator	0m Model: gemini-3.8-flash Args: null Results: null Tokens: input: 14589 output: 279 thoughts: 1443 Thoughts: Refactoring the `mem_cgroup` Structure: KMSAN Analysis Okay, so I'm looking at this patch and it's pretty straightforward. The goal here is a pure refactoring of the `struct mem_cgroup`. Specifically, it's about tidying up the legacy cgroup v1 fields by embedding them within a dedicated sub-structure, `struct mem_cgroup_v1 v1`. The patch then updates all field accesses, changing `memcg->field` to `memcg->v1.field` across the relevant files like `mm/memcontrol.c`, `mm/memcontrol-v1.c`, and the associated headers. I quickly checked the code. It appears all existing members are now accessed through the nested `v1` structure. I made sure to check the diff thoroughly: documentation added to note `struct mem_cgroup_v1`, changes in headers to declare the structure, and then the systematic updates within the source files. I also wanted to quickly be certain no other aspects of the structure were altered. No new fields, no modifications to existing ones beyond the nesting and renaming, or changes to how `mem_cgroup` is utilized. Now, a critical point for my analysis: memory safety, and specifically, KMSAN. I need to make sure this refactoring doesn't introduce any uninitialized memory risks. The initial allocation of `struct mem_cgroup` is handled by `kmem_cache_zalloc(memcg_cachep, GFP_KERNEL);`. This is important because it guarantees that the entire `struct mem_cgroup`, including this new `v1` sub-structure, is zero-initialized at allocation time. That covers my biggest concern. Further checks show that relevant initialization happens in `memcg1_memcg_init()` and `mem_cgroup_css_alloc()`. I considered possible copy operations of `mem_cgroup_v1`, but it's only embedded, never passed by value. There are also no struct copies to user space. There's nothing here that's changing the way memory is laid out or handled; it's a structural change, only. It's just moving the v1 fields inside another structure. No new allocations, and no risk of uninitialized memory reads or information leaks are being introduced. Considering the criteria for `NeedsKMSAN=false`, this patch clearly meets all the criteria. The changes are primarily structural and do not expose any uninitialized memory risks. Any hypothetical bug would likely be caught by KASAN, LOCKDEP or other standard detectors. The structures are zero-initialized. Therefore, I'm confident in setting `NeedsKMSAN=false`. I'll put together the final reasoning in the `set-results` section.
54/3	2026/09/18 03:18	tool	set-results	0m Args: { "KMSANReasoning": "This patch is a mechanical refactoring that groups legacy cgroup v1 fields within struct mem_cgroup into a separate struct mem_cgroup_v1 (accessed via memcg-\u003ev1.\u003cfield\u003e). \n\n1. Allocation \u0026 Initialization: The parent structure struct mem_cgroup continues to be allocated using kmem_cache_zalloc() in mem_cgroup_alloc(), ensuring all embedded members, including struct mem_cgroup_v1, are completely zero-initialized. Mutexes, list heads, spinlocks, and page counters are initialized exactly as before in mem_cgroup_css_alloc() and memcg1_memcg_init().\n2. Data Flow \u0026 Leak Potential: No kernel memory is copied to user space, no new stack/heap allocations are introduced without zeroing, and no data bounds, lengths, or control flow logic are modified.\n3. KASAN vs KMSAN: KMSAN is designed to detect uninitialized memory reads and information leaks. This patch introduces no uninitialized memory risks. Any structural or pointer issues resulting from refactoring would be caught by standard build checks, KASAN, or LOCKDEP. Thus, a dedicated KMSAN run is not justified.", "NeedsKMSAN": false } Results: { "KMSANReasoning": "This patch is a mechanical refactoring that groups legacy cgroup v1 fields within struct mem_cgroup into a separate struct mem_cgroup_v1 (accessed via memcg-\u003ev1.\u003cfield\u003e). \n\n1. Allocation \u0026 Initialization: The parent structure struct mem_cgroup continues to be allocated using kmem_cache_zalloc() in mem_cgroup_alloc(), ensuring all embedded members, including struct mem_cgroup_v1, are completely zero-initialized. Mutexes, list heads, spinlocks, and page counters are initialized exactly as before in mem_cgroup_css_alloc() and memcg1_memcg_init().\n2. Data Flow \u0026 Leak Potential: No kernel memory is copied to user space, no new stack/heap allocations are introduced without zeroing, and no data bounds, lengths, or control flow logic are modified.\n3. KASAN vs KMSAN: KMSAN is designed to detect uninitialized memory reads and information leaks. This patch introduces no uninitialized memory risks. Any structural or pointer issues resulting from refactoring would be caught by standard build checks, KASAN, or LOCKDEP. Thus, a dedicated KMSAN run is not justified.", "NeedsKMSAN": false }

LLM Calls Summary:
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Tool Calls Summary:
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