AI Trajectory

Trajectory: (Expand/Collapse All)
Seq	Timestamp	Type	Name	Duration
0/0	2026/07/10 00:26	flow	patch-triage	1m Args: null Results: { "EnableConfigs": [ "TRANSPARENT_HUGEPAGE" ], "FocusSymbols": [ "__wp_can_reuse_large_anon_folio", "collect_longterm_unpinnable_folios", "mlock_folio", "mlock_new_folio", "munlock_folio", "folio_rotate_reclaimable", "folio_activate", "folio_add_lru", "deactivate_file_folio", "folio_deactivate", "folio_mark_lazyfree" ], "Reasoning": "The patch modifies the memory management subsystem, specifically the condition for caching folios in the per-CPU LRU cache (`folio_may_be_lru_cached`) and the logic for reusing large anonymous folios during write faults (`__wp_can_reuse_large_anon_folio`). These are functional changes that affect core memory management and page fault handling, which should be fuzzed to ensure no regressions or bugs are introduced.", "WorthFuzzing": true }
1/1	2026/07/10 00:26	action	read-patch-diff	0m Args: null Results: { "PatchDiff": "commit 0cf8ce242fbe6debed46cbfa0be767677f7b7b32\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Fri Jul 10 00:26:56 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/include/linux/swap.h b/include/linux/swap.h\nindex 8f0f68e245baa3..fce1d84aa2c818 100644\n--- a/include/linux/swap.h\n+++ b/include/linux/swap.h\n@@ -322,9 +322,9 @@ static inline bool folio_may_be_lru_cached(struct folio folio)\n \t/\n \t * Holding PMD-sized folios in per-CPU LRU cache unbalances accounting.\n \t * Holding small numbers of low-order mTHP folios in per-CPU LRU cache\n-\t * will be sensible, but nobody has implemented and tested that yet.\n+\t * will be sensible.\n \t /\n-\treturn !folio_test_large(folio);\n+\treturn folio_order(folio) \u003c PAGE_ALLOC_COSTLY_ORDER;\n }\n \n extern atomic_t lru_disable_count;\ndiff --git a/mm/memory.c b/mm/memory.c\nindex ff338c2abe9231..8572228743b2e3 100644\n--- a/mm/memory.c\n+++ b/mm/memory.c\n@@ -4143,6 +4143,19 @@ static bool __wp_can_reuse_large_anon_folio(struct folio folio,\n \t\tfolio_unlock(folio);\n \t}\n \n+\tif (folio_may_be_lru_cached(folio) \u0026\u0026 !folio_test_lru(folio)) {\n+\t\tif (folio_ref_count(folio) \u003e folio_large_mapcount(folio) + 1)\n+\t\t\treturn false;\n+\t\t/\n+\t\t A global LRU drain is too expensive, but a local drain\n+\t\t * can still be beneficial. For example, large folios that\n+\t\t * have just been swapped in and fall back from\n+\t\t * do_swap_page() to do_wp_page() are likely still in this\n+\t\t * CPU's LRU cache.\n+\t\t */\n+\t\tlru_add_drain();\n+\t}\n+\n \tif (folio_large_mapcount(folio) != folio_ref_count(folio))\n \t\treturn false;\n \n" }
2/1	2026/07/10 00:26	agent	patch-evaluator	1m Model: gemini-3.1-pro-preview Args: null Results: { "EnableConfigs": [ "TRANSPARENT_HUGEPAGE" ], "FocusSymbols": [ "__wp_can_reuse_large_anon_folio", "collect_longterm_unpinnable_folios", "mlock_folio", "mlock_new_folio", "munlock_folio", "folio_rotate_reclaimable", "folio_activate", "folio_add_lru", "deactivate_file_folio", "folio_deactivate", "folio_mark_lazyfree" ], "Reasoning": "The patch modifies the memory management subsystem, specifically the condition for caching folios in the per-CPU LRU cache (`folio_may_be_lru_cached`) and the logic for reusing large anonymous folios during write faults (`__wp_can_reuse_large_anon_folio`). These are functional changes that affect core memory management and page fault handling, which should be fuzzed to ensure no regressions or bugs are introduced.", "WorthFuzzing": true } Instruction: You are an expert Linux kernel maintainer. Your job is to review a provided patch series and determine if it makes functional changes to the kernel that should be fuzzed. IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in your workspace. Do NOT rely on your internal knowledge of the kernel. You must actively use your code access tools to examine the actual source code and confirm any assumptions. Return WorthFuzzing=false if the patch only contains: - Modifications to Documentation/, Kconfig files, or code comments. - Purely decorative changes, such as logging (e.g., pr_err, printk) or tracepoints. - Changes to numeric constants or macros that do not functionally alter execution flow. - Code paths that are impossible to reach in virtualized environments like GCE or QEMU, even when utilizing software-emulated hardware (e.g., usb gadget, mac80211_hwsim). If it modifies reachable core kernel logic, drivers, or architectures, use your code search tools to verify the code can be executed, then return WorthFuzzing=true. When returning WorthFuzzing=true, you MUST ALSO: 1. Extract any specific kernel functions that should be heavily fuzzed into FocusSymbols. Avoid listing generic hot-path functions to prevent skewed test distributions. 2. Identify any specific CONFIG_ options required to properly test this new/modified feature. Go and look into the Kconfig files and check for ifdefs around the code, do not make assumptions. Do not list too generic configs (we already have them enabled). Only list those that specifically cover the modified code. List them in the EnableConfigs output array, and DO NOT add a '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: For your convenience, here is the diff of the changes: commit 0cf8ce242fbe6debed46cbfa0be767677f7b7b32 Author: syz-cluster <triage@syzkaller.com> Date: Fri Jul 10 00:26:56 2026 +0000 syz-cluster: applied patch under review diff --git a/include/linux/swap.h b/include/linux/swap.h index 8f0f68e245baa3..fce1d84aa2c818 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -322,9 +322,9 @@ static inline bool folio_may_be_lru_cached(struct folio folio) / * Holding PMD-sized folios in per-CPU LRU cache unbalances accounting. * Holding small numbers of low-order mTHP folios in per-CPU LRU cache - * will be sensible, but nobody has implemented and tested that yet. + * will be sensible. / - return !folio_test_large(folio); + return folio_order(folio) < PAGE_ALLOC_COSTLY_ORDER; } extern atomic_t lru_disable_count; diff --git a/mm/memory.c b/mm/memory.c index ff338c2abe9231..8572228743b2e3 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4143,6 +4143,19 @@ static bool __wp_can_reuse_large_anon_folio(struct folio folio, folio_unlock(folio); } + if (folio_may_be_lru_cached(folio) && !folio_test_lru(folio)) { + if (folio_ref_count(folio) > folio_large_mapcount(folio) + 1) + return false; + /* + * A global LRU drain is too expensive, but a local drain + * can still be beneficial. For example, large folios that + * have just been swapped in and fall back from + * do_swap_page() to do_wp_page() are likely still in this + * CPU's LRU cache. + */ + lru_add_drain(); + } + if (folio_large_mapcount(folio) != folio_ref_count(folio)) return false;
3/2	2026/07/10 00:26	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 2180 output: 26 thoughts: 311 Thoughts: Analyzing a Recent Swap Patch Okay, so I'm looking at this patch and it seems like it's a relatively focused change within the memory management subsystem, specifically concerning how we handle large anonymous folios during write faults. The core of the change lies in a couple of key modifications. First, they've altered `folio_may_be_lru_cached` in `include/linux/swap.h`. Previously, it was checking if a folio wasn't large using `!folio_test_large(folio)`. Now, it's checking if the folio's order is less than `PAGE_ALLOC_COSTLY_ORDER`. This subtly shifts the definition of what we consider eligible for LRU caching. I need to think about the implications here. Are there scenarios where this new check might lead to different behavior, perhaps more or fewer folios being considered for LRU? I'll have to investigate that further, thinking about the performance ramifications, especially around swapping. Then, the second part of the change introduces new logic inside `__wp_can_reuse_large_anon_folio` in `mm/memory.c`. It adds a conditional check that now includes this new `folio_may_be_lru_cached` criterion, plus a further condition that the folio is not currently on the LRU (`!folio_test_lru(folio)`). What really catches my eye is this `if` block. It seems to be trying to improve large anonymous folio reuse in scenarios where they're recently swapped in. If the folio is a candidate for the LRU, but not actually on it, the code attempts to drain the LRU. This is likely to prevent the costly global LRU drain. The comment hints at optimizations to improve the likelihood of reuse for folios that were recently swapped in. So, in essence, this is a functional modification aimed at improving write fault performance, particularly when large anonymous folios are involved. It's about making smarter decisions about when to reuse these large folios, potentially reducing page faults and improving overall system responsiveness. I want to delve deeper into the rationale for this, and see if it is going to cause any regressions, or conflicts.
4/2	2026/07/10 00:27	tool	grepper	0m Args: { "Expression": "__wp_can_reuse_large_anon_folio" } Results: { "Output": "mm/memory.c=4067=static vm_fault_t wp_page_shared(struct vm_fault vmf, struct folio folio)\n--\nmm/memory.c-4107-#ifdef CONFIG_TRANSPARENT_HUGEPAGE\nmm/memory.c:4108:static bool __wp_can_reuse_large_anon_folio(struct folio folio,\nmm/memory.c-4109-\t\tstruct vm_area_struct vma)\n--\nmm/memory.c-4186-#else /* !CONFIG_TRANSPARENT_HUGEPAGE /\nmm/memory.c:4187:static bool __wp_can_reuse_large_anon_folio(struct folio folio,\nmm/memory.c-4188-\t\tstruct vm_area_struct vma)\n--\nmm/memory.c=4194=static bool wp_can_reuse_anon_folio(struct folio folio,\n--\nmm/memory.c-4197-\tif (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) \u0026\u0026 folio_test_large(folio))\nmm/memory.c:4198:\t\treturn __wp_can_reuse_large_anon_folio(folio, vma);\nmm/memory.c-4199-\n" }
5/2	2026/07/10 00:27	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 3315 output: 24 thoughts: 66 Thoughts: Okay, let's break this down. Understanding Folio Reusability with Transparent Hugepages Alright, so the function `__wp_can_reuse_large_anon_folio`... that's exclusively defined under the `CONFIG_TRANSPARENT_HUGEPAGE` conditional. That immediately tells me that Transparent Hugepages are a hard requirement for this function to even exist. Without that configuration, this code path is simply not compiled, making the function irrelevant. This is a crucial dependency to remember when considering how the overall memory management system behaves. It's a key piece in the puzzle of large page optimization, so I need to keep that in mind. Now, my next question is regarding its interaction with other processes, let's explore `folio_may_be_lru_cached`.
6/2	2026/07/10 00:27	tool	grepper	0m Args: { "Expression": "folio_may_be_lru_cached" } Results: { "Output": "include/linux/swap.h=318=void folio_mark_accessed(struct folio );\ninclude/linux/swap.h-319-\ninclude/linux/swap.h:320:static inline bool folio_may_be_lru_cached(struct folio folio)\ninclude/linux/swap.h-321-{\n--\nmm/gup.c=2265=static unsigned long collect_longterm_unpinnable_folios(\n--\nmm/gup.c-2289-\nmm/gup.c:2290:\t\tif (drained == 0 \u0026\u0026 folio_may_be_lru_cached(folio) \u0026\u0026\nmm/gup.c-2291-\t\t\t\tfolio_ref_count(folio) !=\n--\nmm/gup.c-2295-\t\t}\nmm/gup.c:2296:\t\tif (drained == 1 \u0026\u0026 folio_may_be_lru_cached(folio) \u0026\u0026\nmm/gup.c-2297-\t\t\t\tfolio_ref_count(folio) !=\n--\nmm/memory.c=4108=static bool __wp_can_reuse_large_anon_folio(struct folio folio,\n--\nmm/memory.c-4145-\nmm/memory.c:4146:\tif (folio_may_be_lru_cached(folio) \u0026\u0026 !folio_test_lru(folio)) {\nmm/memory.c-4147-\t\tif (folio_ref_count(folio) \u003e folio_large_mapcount(folio) + 1)\n--\nmm/mlock.c=242=void mlock_folio(struct folio folio)\n--\nmm/mlock.c-257-\tif (!folio_batch_add(fbatch, mlock_lru(folio)) \|\|\nmm/mlock.c:258:\t !folio_may_be_lru_cached(folio) \|\| lru_cache_disabled())\nmm/mlock.c-259-\t\tmlock_folio_batch(fbatch);\n--\nmm/mlock.c=267=void mlock_new_folio(struct folio folio)\n--\nmm/mlock.c-280-\tif (!folio_batch_add(fbatch, mlock_new(folio)) \|\|\nmm/mlock.c:281:\t !folio_may_be_lru_cached(folio) \|\| lru_cache_disabled())\nmm/mlock.c-282-\t\tmlock_folio_batch(fbatch);\n--\nmm/mlock.c=290=void munlock_folio(struct folio folio)\n--\nmm/mlock.c-301-\tif (!folio_batch_add(fbatch, folio) \|\|\nmm/mlock.c:302:\t !folio_may_be_lru_cached(folio) \|\| lru_cache_disabled())\nmm/mlock.c-303-\t\tmlock_folio_batch(fbatch);\n--\nmm/swap.c=217=static void __folio_batch_add_and_move(struct folio_batch __percpu *fbatch,\n--\nmm/swap.c-229-\tif (!folio_batch_add(this_cpu_ptr(fbatch), folio) \|\|\nmm/swap.c:230:\t\t\t!folio_may_be_lru_cached(folio) \|\| lru_cache_disabled())\nmm/swap.c-231-\t\tfolio_batch_move_lru(this_cpu_ptr(fbatch), move_fn);\n" }
7/2	2026/07/10 00:27	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 4465 output: 23 thoughts: 147 Thoughts: Analyzing the Memory Management Patch Okay, so this patch is definitely working as intended. I see it's dealing with memory management, specifically how those large, anonymous folios are handled when a write fault occurs. It's also touching the logic around `folio_may_be_lru_cached`. Let's see, which symbols should I focus on? `__wp_can_reuse_large_anon_folio` looks like a good starting point. I know `folio_may_be_lru_cached` is an inline function, so it's not a symbol I can just jump to. Ah, right, `wp_can_reuse_anon_folio` is the caller of that inline function. And, since we're talking about write faults, `do_wp_page` is the caller of that function. Alright, I'll start with digging into `wp_can_reuse_anon_folio` and see what's going on.
8/2	2026/07/10 00:27	tool	grepper	0m Args: { "Expression": "wp_can_reuse_anon_folio" } Results: { "Output": "mm/memory.c=4187=static bool __wp_can_reuse_large_anon_folio(struct folio folio,\n--\nmm/memory.c-4193-\nmm/memory.c:4194:static bool wp_can_reuse_anon_folio(struct folio folio,\nmm/memory.c-4195-\t\t\t\t struct vm_area_struct vma)\n--\nmm/memory.c=4257=static vm_fault_t do_wp_page(struct vm_fault vmf)\n--\nmm/memory.c-4327-\tif (folio \u0026\u0026 folio_test_anon(folio) \u0026\u0026\nmm/memory.c:4328:\t (PageAnonExclusive(vmf-\u003epage) \|\| wp_can_reuse_anon_folio(folio, vma))) {\nmm/memory.c-4329-\t\tif (!PageAnonExclusive(vmf-\u003epage))\n" }
9/2	2026/07/10 00:27	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 5084 output: 22 thoughts: 127 Thoughts: Analyzing Memory Re-use Paths Okay, so `do_wp_page` is definitely a performance bottleneck, a hot path as they say, but I think focusing on `__wp_can_reuse_large_anon_folio` might be more productive right now. It's a more targeted function. I'm going to use that as my primary focus. First, let's verify the setup. I already know that `TRANSPARENT_HUGEPAGE` is a hard requirement for `__wp_can_reuse_large_anon_folio` to even be relevant. I need to keep that in mind. Now, let me see if there are other relevant configurations. Ah, here's one: `PAGE_ALLOC_COSTLY_ORDER`. I see it's used within `folio_may_be_lru_cached`. It looks like it's just a constant, but its context could be crucial to determining why certain re-use pathways might be more optimal than others. I'll need to dig into how this value impacts allocation.
10/2	2026/07/10 00:27	tool	grepper	0m Args: { "Expression": "PAGE_ALLOC_COSTLY_ORDER" } Results: { "Output": "Documentation/admin-guide/mm/slab.rst=150=can be influenced by kernel parameters:\n--\nDocumentation/admin-guide/mm/slab.rst-153-.. slab_min_order=x\t\t(default 0)\nDocumentation/admin-guide/mm/slab.rst:154:.. slab_max_order=x\t\t(default 3 (PAGE_ALLOC_COSTLY_ORDER))\nDocumentation/admin-guide/mm/slab.rst-155-\n--\ndrivers/net/ethernet/amd/xgbe/xgbe-desc.c=247=static int xgbe_map_rx_buffer(struct xgbe_prv_data pdata,\n--\ndrivers/net/ethernet/amd/xgbe/xgbe-desc.c-260-\t\tret = xgbe_alloc_pages(pdata, \u0026ring-\u003erx_buf_pa,\ndrivers/net/ethernet/amd/xgbe/xgbe-desc.c:261:\t\t\t\t PAGE_ALLOC_COSTLY_ORDER, ring-\u003enode);\ndrivers/net/ethernet/amd/xgbe/xgbe-desc.c-262-\t\tif (ret)\n--\ndrivers/net/ethernet/synopsys/dwc-xlgmac-desc.c=385=static int xlgmac_map_rx_buffer(struct xlgmac_pdata pdata,\n--\ndrivers/net/ethernet/synopsys/dwc-xlgmac-desc.c-398-\tif (!ring-\u003erx_buf_pa.pages) {\ndrivers/net/ethernet/synopsys/dwc-xlgmac-desc.c:399:\t\torder = max_t(int, PAGE_ALLOC_COSTLY_ORDER - 1, 0);\ndrivers/net/ethernet/synopsys/dwc-xlgmac-desc.c-400-\t\tret = xlgmac_alloc_pages(pdata, \u0026ring-\u003erx_buf_pa,\n--\ndrivers/net/tap.c=543=static inline struct sk_buff tap_alloc_skb(struct sock sk, size_t prepad,\n--\ndrivers/net/tap.c-552-\ndrivers/net/tap.c:553:\tif (len - linear \u003e MAX_SKB_FRAGS * (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER))\ndrivers/net/tap.c:554:\t\tlinear = len - MAX_SKB_FRAGS * (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER);\ndrivers/net/tap.c-555-\tskb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,\ndrivers/net/tap.c:556:\t\t\t\t err, PAGE_ALLOC_COSTLY_ORDER);\ndrivers/net/tap.c-557-\tif (!skb)\n--\ndrivers/net/tun.c=1480=static struct sk_buff tun_alloc_skb(struct tun_file tfile,\n--\ndrivers/net/tun.c-1491-\ndrivers/net/tun.c:1492:\tif (len - linear \u003e MAX_SKB_FRAGS * (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER))\ndrivers/net/tun.c:1493:\t\tlinear = len - MAX_SKB_FRAGS * (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER);\ndrivers/net/tun.c-1494-\tskb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,\ndrivers/net/tun.c:1495:\t\t\t\t \u0026err, PAGE_ALLOC_COSTLY_ORDER);\ndrivers/net/tun.c-1496-\tif (!skb)\n--\nfs/fuse/file.c=2351=static void fuse_vma_close(struct vm_area_struct vma)\n--\nfs/fuse/file.c-2371- - sync(2)\nfs/fuse/file.c:2372: * - try_to_free_pages() with order \u003e PAGE_ALLOC_COSTLY_ORDER\nfs/fuse/file.c-2373- /\n--\nfs/gfs2/glock.c=2580=static const struct seq_operations gfs2_sbstats_sops = {\n--\nfs/gfs2/glock.c-2586-\nfs/gfs2/glock.c:2587:#define GFS2_SEQ_GOODSIZE min(PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER, 65536UL)\nfs/gfs2/glock.c-2588-\n--\ninclude/linux/gfp_types.h=26=enum {\n--\ninclude/linux/gfp_types.h-207- The default allocator behavior depends on the request size. We have a concept\ninclude/linux/gfp_types.h:208: * of so-called costly allocations (with order \u003e %PAGE_ALLOC_COSTLY_ORDER).\ninclude/linux/gfp_types.h-209- * !costly allocations are too essential to fail so they are implicitly\n--\ninclude/linux/mmzone.h-57-/\ninclude/linux/mmzone.h:58: PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed\ninclude/linux/mmzone.h-59- * costly to service. That is between allocation orders which should\n--\ninclude/linux/mmzone.h-62- /\ninclude/linux/mmzone.h:63:#define PAGE_ALLOC_COSTLY_ORDER 3\ninclude/linux/mmzone.h-64-\n--\ninclude/linux/mmzone.h=797=enum zone_watermarks {\n--\ninclude/linux/mmzone.h-805-/\ninclude/linux/mmzone.h:806: * One per migratetype for each PAGE_ALLOC_COSTLY_ORDER. Two additional lists\ninclude/linux/mmzone.h-807- * are added for THP. One PCP list is used by GPF_MOVABLE, and the other PCP list\n--\ninclude/linux/mmzone.h-814-#endif\ninclude/linux/mmzone.h:815:#define NR_LOWORDER_PCP_LISTS (MIGRATE_PCPTYPES * (PAGE_ALLOC_COSTLY_ORDER + 1))\ninclude/linux/mmzone.h-816-#define NR_PCP_LISTS (NR_LOWORDER_PCP_LISTS + NR_PCP_THP)\n--\ninclude/linux/swap.h=320=static inline bool folio_may_be_lru_cached(struct folio folio)\n--\ninclude/linux/swap.h-326-\t /\ninclude/linux/swap.h:327:\treturn folio_order(folio) \u003c PAGE_ALLOC_COSTLY_ORDER;\ninclude/linux/swap.h-328-}\n--\ninclude/linux/virtio_vsock.h=61=__virtio_vsock_alloc_skb_with_frags(unsigned int header_len,\n--\ninclude/linux/virtio_vsock.h-68-\tskb = alloc_skb_with_frags(header_len, data_len,\ninclude/linux/virtio_vsock.h:69:\t\t\t\t PAGE_ALLOC_COSTLY_ORDER, \u0026err, mask);\ninclude/linux/virtio_vsock.h-70-\tif (!skb)\n--\ninclude/linux/virtio_vsock.h=84=static inline struct sk_buff virtio_vsock_alloc_skb(unsigned int size, gfp_t mask)\ninclude/linux/virtio_vsock.h-85-{\ninclude/linux/virtio_vsock.h:86:\tif (size \u003c= SKB_WITH_OVERHEAD(PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER))\ninclude/linux/virtio_vsock.h-87-\t\treturn virtio_vsock_alloc_linear_skb(size, mask);\n--\nkernel/bpf/syscall.c=373=static void __bpf_map_area_alloc(u64 size, int numa_node, bool mmapable)\n--\nkernel/bpf/syscall.c-397-\t\tflags = VM_USERMAP;\nkernel/bpf/syscall.c:398:\t} else if (size \u003c= (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER)) {\nkernel/bpf/syscall.c-399-\t\tarea = kmalloc_node(size, gfp \| GFP_USER \| __GFP_NORETRY,\n--\nmm/compaction.c=276=__reset_isolation_pfn(struct zone zone, unsigned long pfn, bool check_source,\n--\nmm/compaction.c-337-\nmm/compaction.c:338:\t\tpage += (1 \u003c\u003c PAGE_ALLOC_COSTLY_ORDER);\nmm/compaction.c-339-\t} while (page \u003c= end_page);\n--\nmm/compaction.c=1939=static unsigned long fast_find_migrateblock(struct compact_control cc)\n--\nmm/compaction.c-1972-\t /\nmm/compaction.c:1973:\tif (cc-\u003eorder \u003c= PAGE_ALLOC_COSTLY_ORDER)\nmm/compaction.c-1974-\t\treturn pfn;\n--\nmm/compaction.c-1996-\tfor (order = cc-\u003eorder - 1;\nmm/compaction.c:1997:\t order \u003e= PAGE_ALLOC_COSTLY_ORDER \u0026\u0026 !found_block \u0026\u0026 nr_scanned \u003c limit;\nmm/compaction.c-1998-\t order--) {\n--\nmm/compaction.c=2374=static bool __compaction_suitable(struct zone zone, int order,\n--\nmm/compaction.c-2394-\twatermark += compact_gap(order);\nmm/compaction.c:2395:\tif (order \u003e PAGE_ALLOC_COSTLY_ORDER)\nmm/compaction.c-2396-\t\twatermark += low_wmark_pages(zone) - min_wmark_pages(zone);\n--\nmm/compaction.c=2404=bool compaction_suitable(struct zone zone, int order, unsigned long watermark,\n--\nmm/compaction.c-2429-\t\tcompact_result = COMPACT_CONTINUE;\nmm/compaction.c:2430:\t\tif (order \u003e PAGE_ALLOC_COSTLY_ORDER) {\nmm/compaction.c-2431-\t\t\tint fragindex = fragmentation_index(zone, order);\n--\nmm/compaction.c=2491=compaction_suit_allocation_order(struct zone zone, unsigned int order,\n--\nmm/compaction.c-2516-\t /\nmm/compaction.c:2517:\tif (order \u003e PAGE_ALLOC_COSTLY_ORDER \u0026\u0026 async \u0026\u0026\nmm/compaction.c-2518-\t !(alloc_flags \u0026 ALLOC_CMA)) {\n--\nmm/kasan/hw_tags.c=73=unsigned long kasan_page_alloc_sample = PAGE_ALLOC_SAMPLE_DEFAULT;\n--\nmm/kasan/hw_tags.c-77- The default value is chosen to match both\nmm/kasan/hw_tags.c:78: * PAGE_ALLOC_COSTLY_ORDER and SKB_FRAG_PAGE_ORDER.\nmm/kasan/hw_tags.c-79- /\n--\nmm/memcontrol.c=1918=static bool mem_cgroup_oom(struct mem_cgroup memcg, gfp_t mask, int order)\n--\nmm/memcontrol.c-1921-\nmm/memcontrol.c:1922:\tif (order \u003e PAGE_ALLOC_COSTLY_ORDER)\nmm/memcontrol.c-1923-\t\treturn false;\n--\nmm/memcontrol.c=2595=static int try_charge_memcg(struct mem_cgroup memcg, gfp_t gfp_mask,\n--\nmm/memcontrol.c-2678-\t /\nmm/memcontrol.c:2679:\tif (nr_reclaimed \u0026\u0026 nr_pages \u003c= (1 \u003c\u003c PAGE_ALLOC_COSTLY_ORDER))\nmm/memcontrol.c-2680-\t\tgoto retry;\n--\nmm/page_alloc.c=651=static inline unsigned int order_to_pindex(int migratetype, int order)\n--\nmm/page_alloc.c-655-\nmm/page_alloc.c:656:\t\tif (order \u003e PAGE_ALLOC_COSTLY_ORDER)\nmm/page_alloc.c-657-\t\t\treturn NR_LOWORDER_PCP_LISTS + movable;\n--\nmm/page_alloc.c=675=static inline bool pcp_allowed_order(unsigned int order)\nmm/page_alloc.c-676-{\nmm/page_alloc.c:677:\tif (order \u003c= PAGE_ALLOC_COSTLY_ORDER)\nmm/page_alloc.c-678-\t\treturn true;\n--\nmm/page_alloc.c=2832=static bool free_frozen_page_commit(struct zone zone,\n--\nmm/page_alloc.c-2860-\t /\nmm/page_alloc.c:2861:\tif (order \u0026\u0026 order \u003c= PAGE_ALLOC_COSTLY_ORDER) {\nmm/page_alloc.c-2862-\t\tfree_high = (pcp-\u003efree_count \u003e= (batch + pcp-\u003ehigh_min / 2) \u0026\u0026\n--\nmm/page_alloc.c=4047=__alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,\n--\nmm/page_alloc.c-4087-\t/* The OOM killer will not help higher order allocs /\nmm/page_alloc.c:4088:\tif (order \u003e PAGE_ALLOC_COSTLY_ORDER)\nmm/page_alloc.c-4089-\t\tgoto out;\n--\nmm/page_alloc.c=4202=should_compact_retry(gfp_t gfp_mask, struct alloc_context ac, int order,\n--\nmm/page_alloc.c-4243-\t\t /\nmm/page_alloc.c:4244:\t\tif (order \u003e PAGE_ALLOC_COSTLY_ORDER)\nmm/page_alloc.c-4245-\t\t\tmax_retries /= 4;\n--\nmm/page_alloc.c-4255-\t /\nmm/page_alloc.c:4256:\tmin_priority = (order \u003e PAGE_ALLOC_COSTLY_ORDER) ?\nmm/page_alloc.c-4257-\t\t\tMIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY;\n--\nmm/page_alloc.c=4279=should_compact_retry(gfp_t gfp_mask, struct alloc_context ac, int order,\n--\nmm/page_alloc.c-4287-\nmm/page_alloc.c:4288:\tif (!order \|\| order \u003e PAGE_ALLOC_COSTLY_ORDER)\nmm/page_alloc.c-4289-\t\treturn false;\n--\nmm/page_alloc.c=4581=should_reclaim_retry(gfp_t gfp_mask, unsigned order,\n--\nmm/page_alloc.c-4593-\t /\nmm/page_alloc.c:4594:\tif (did_some_progress \u0026\u0026 order \u003c= PAGE_ALLOC_COSTLY_ORDER)\nmm/page_alloc.c-4595-\t\tno_progress_loops = 0;\n--\nmm/page_alloc.c=4725=__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,\n--\nmm/page_alloc.c-4730-\tbool nofail = gfp_mask \u0026 __GFP_NOFAIL;\nmm/page_alloc.c:4731:\tconst bool costly_order = order \u003e PAGE_ALLOC_COSTLY_ORDER;\nmm/page_alloc.c-4732-\tstruct page page = NULL;\n--\nmm/slub.c=7487=static unsigned int slub_max_order =\nmm/slub.c:7488:\tIS_ENABLED(CONFIG_SLUB_TINY) ? 1 : PAGE_ALLOC_COSTLY_ORDER;\nmm/slub.c-7489-static unsigned int slub_min_objects;\n--\nmm/vmpressure.c=240=void vmpressure(gfp_t gfp, int order, struct mem_cgroup memcg, bool tree,\n--\nmm/vmpressure.c-318-\t\t /\nmm/vmpressure.c:319:\t\tif (level \u003e VMPRESSURE_LOW \u0026\u0026 order \u003c= PAGE_ALLOC_COSTLY_ORDER) {\nmm/vmpressure.c-320-\t\t\t/\n--\nmm/vmscan.c=5998=static bool in_reclaim_compaction(struct scan_control sc)\n--\nmm/vmscan.c-6000-\tif (gfp_compaction_allowed(sc-\u003egfp_mask) \u0026\u0026 sc-\u003eorder \u0026\u0026\nmm/vmscan.c:6001:\t\t\t(sc-\u003eorder \u003e PAGE_ALLOC_COSTLY_ORDER \|\|\nmm/vmscan.c-6002-\t\t\t sc-\u003epriority \u003c DEF_PRIORITY - 2))\n--\nmm/vmscan.c=6331=static void shrink_zones(struct zonelist zonelist, struct scan_control sc)\n--\nmm/vmscan.c-6372-\t\t\tif (IS_ENABLED(CONFIG_COMPACTION) \u0026\u0026\nmm/vmscan.c:6373:\t\t\t sc-\u003eorder \u003e PAGE_ALLOC_COSTLY_ORDER \u0026\u0026\nmm/vmscan.c-6374-\t\t\t compaction_ready(zone, sc)) {\n--\nnet/core/net-sysfs.c=1067=static ssize_t store_rps_dev_flow_table_cnt(struct netdev_rx_queue queue,\n--\nnet/core/net-sysfs.c-1096-\t\t\t PAGE_SIZE);\nnet/core/net-sysfs.c:1097:\t\tif (sz \u003c= (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER) \|\|\nnet/core/net-sysfs.c-1098-\t\t is_power_of_2(sizeof(table)))\n--\nnet/ipv4/tcp_input.c=5519=int tcp_send_rcvq(struct sock sk, struct msghdr msg, size_t size)\n--\nnet/ipv4/tcp_input.c-5535-\tskb = alloc_skb_with_frags(size - data_len, data_len,\nnet/ipv4/tcp_input.c:5536:\t\t\t\t PAGE_ALLOC_COSTLY_ORDER,\nnet/ipv4/tcp_input.c-5537-\t\t\t\t \u0026err, sk-\u003esk_allocation);\n--\nnet/packet/af_packet.c=2919=static struct sk_buff packet_alloc_skb(struct sock sk, size_t prepad,\n--\nnet/packet/af_packet.c-2929-\nnet/packet/af_packet.c:2930:\tif (len - linear \u003e MAX_SKB_FRAGS * (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER))\nnet/packet/af_packet.c:2931:\t\tlinear = len - MAX_SKB_FRAGS * (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER);\nnet/packet/af_packet.c-2932-\tskb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,\nnet/packet/af_packet.c:2933:\t\t\t\t err, PAGE_ALLOC_COSTLY_ORDER);\nnet/packet/af_packet.c-2934-\tif (!skb)\n--\nnet/tls/tls.h-43-\nnet/tls/tls.h:44:#define TLS_PAGE_ORDER\t(min_t(unsigned int, PAGE_ALLOC_COSTLY_ORDER,\t\\\nnet/tls/tls.h-45-\t\t\t TLS_MAX_PAYLOAD_SIZE \u003e\u003e PAGE_SHIFT))\n--\nnet/unix/af_unix.c=2082=static int unix_dgram_sendmsg(struct socket sock, struct msghdr msg,\n--\nnet/unix/af_unix.c-2137-\t\t\t\t msg-\u003emsg_flags \u0026 MSG_DONTWAIT, \u0026err,\nnet/unix/af_unix.c:2138:\t\t\t\t PAGE_ALLOC_COSTLY_ORDER);\nnet/unix/af_unix.c-2139-\tif (!skb)\n--\ntools/include/linux/gfp_types.h=26=enum {\n--\ntools/include/linux/gfp_types.h-207- * The default allocator behavior depends on the request size. We have a concept\ntools/include/linux/gfp_types.h:208: * of so-called costly allocations (with order \u003e %PAGE_ALLOC_COSTLY_ORDER).\ntools/include/linux/gfp_types.h-209- * !costly allocations are too essential to fail so they are implicitly\n" }
11/2	2026/07/10 00:27	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 10802 output: 26 thoughts: 199 Thoughts: Analyzing the Configuration Dependencies for a Kernel Patch Okay, so I'm looking at this kernel patch and figuring out its configuration requirements. The macro `PAGE_ALLOC_COSTLY_ORDER` is defined as `3` in `include/linux/mmzone.h`. Since it's a hardcoded value, there's no specific configuration knob I need to worry about for it. Good, that simplifies things. The real focus here is on `TRANSPARENT_HUGEPAGE`, it seems. That's the only config that really matters, and I want to confirm that. Let's see... the code's touching `folio_may_be_lru_cached`, and I know that function is used across a number of key memory management files: `mm/gup.c`, `mm/memory.c`, `mm/mlock.c`, and `mm/swap.c`. These are core components, so any dependencies there are critical to understand. This patch, in particular, is changing `__wp_can_reuse_large_anon_folio`, which is guarded by `CONFIG_TRANSPARENT_HUGEPAGE`. That's a strong indicator. It confirms that `TRANSPARENT_HUGEPAGE` is the only explicit dependency. Just to be absolutely sure, I'm going to take a closer look at `mm/memory.c` one more time. I've got a good mental map of this code, but it's always worth a quick scan to make sure there aren't any subtle, easily-missed configs lurking in there. Better safe than sorry.
12/2	2026/07/10 00:27	tool	grepper	0m Args: { "Expression": "__wp_can_reuse_large_anon_folio" } Results: { "Output": "mm/memory.c=4067=static vm_fault_t wp_page_shared(struct vm_fault vmf, struct folio folio)\n--\nmm/memory.c-4107-#ifdef CONFIG_TRANSPARENT_HUGEPAGE\nmm/memory.c:4108:static bool __wp_can_reuse_large_anon_folio(struct folio folio,\nmm/memory.c-4109-\t\tstruct vm_area_struct vma)\n--\nmm/memory.c-4186-#else /* !CONFIG_TRANSPARENT_HUGEPAGE /\nmm/memory.c:4187:static bool __wp_can_reuse_large_anon_folio(struct folio folio,\nmm/memory.c-4188-\t\tstruct vm_area_struct vma)\n--\nmm/memory.c=4194=static bool wp_can_reuse_anon_folio(struct folio folio,\n--\nmm/memory.c-4197-\tif (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) \u0026\u0026 folio_test_large(folio))\nmm/memory.c:4198:\t\treturn __wp_can_reuse_large_anon_folio(folio, vma);\nmm/memory.c-4199-\n" }
13/2	2026/07/10 00:27	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 11705 output: 24 thoughts: 50 Thoughts: Okay, here's my take on those thoughts, framed as my own: Digging into THP Cache Optimization Right, CONFIG_TRANSPARENT_HUGEPAGE... that's the key. That's the one we're interested in for our current line of inquiry. Now, let's see if we can identify other interesting locations to focus on. Let's see where the function folio_may_be_lru_cached is used. Are there other uses of that function that we can make note of, and use as focus symbols for the study?
14/2	2026/07/10 00:27	tool	grepper	0m Args: { "Expression": "folio_may_be_lru_cached" } Results: { "Output": "include/linux/swap.h=318=void folio_mark_accessed(struct folio );\ninclude/linux/swap.h-319-\ninclude/linux/swap.h:320:static inline bool folio_may_be_lru_cached(struct folio folio)\ninclude/linux/swap.h-321-{\n--\nmm/gup.c=2265=static unsigned long collect_longterm_unpinnable_folios(\n--\nmm/gup.c-2289-\nmm/gup.c:2290:\t\tif (drained == 0 \u0026\u0026 folio_may_be_lru_cached(folio) \u0026\u0026\nmm/gup.c-2291-\t\t\t\tfolio_ref_count(folio) !=\n--\nmm/gup.c-2295-\t\t}\nmm/gup.c:2296:\t\tif (drained == 1 \u0026\u0026 folio_may_be_lru_cached(folio) \u0026\u0026\nmm/gup.c-2297-\t\t\t\tfolio_ref_count(folio) !=\n--\nmm/memory.c=4108=static bool __wp_can_reuse_large_anon_folio(struct folio folio,\n--\nmm/memory.c-4145-\nmm/memory.c:4146:\tif (folio_may_be_lru_cached(folio) \u0026\u0026 !folio_test_lru(folio)) {\nmm/memory.c-4147-\t\tif (folio_ref_count(folio) \u003e folio_large_mapcount(folio) + 1)\n--\nmm/mlock.c=242=void mlock_folio(struct folio folio)\n--\nmm/mlock.c-257-\tif (!folio_batch_add(fbatch, mlock_lru(folio)) \|\|\nmm/mlock.c:258:\t !folio_may_be_lru_cached(folio) \|\| lru_cache_disabled())\nmm/mlock.c-259-\t\tmlock_folio_batch(fbatch);\n--\nmm/mlock.c=267=void mlock_new_folio(struct folio folio)\n--\nmm/mlock.c-280-\tif (!folio_batch_add(fbatch, mlock_new(folio)) \|\|\nmm/mlock.c:281:\t !folio_may_be_lru_cached(folio) \|\| lru_cache_disabled())\nmm/mlock.c-282-\t\tmlock_folio_batch(fbatch);\n--\nmm/mlock.c=290=void munlock_folio(struct folio folio)\n--\nmm/mlock.c-301-\tif (!folio_batch_add(fbatch, folio) \|\|\nmm/mlock.c:302:\t !folio_may_be_lru_cached(folio) \|\| lru_cache_disabled())\nmm/mlock.c-303-\t\tmlock_folio_batch(fbatch);\n--\nmm/swap.c=217=static void __folio_batch_add_and_move(struct folio_batch __percpu *fbatch,\n--\nmm/swap.c-229-\tif (!folio_batch_add(this_cpu_ptr(fbatch), folio) \|\|\nmm/swap.c:230:\t\t\t!folio_may_be_lru_cached(folio) \|\| lru_cache_disabled())\nmm/swap.c-231-\t\tfolio_batch_move_lru(this_cpu_ptr(fbatch), move_fn);\n" }
15/2	2026/07/10 00:27	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 12797 output: 24 thoughts: 189 Thoughts: Fuzzing Target Identification Okay, let's see, I've got a good starting point for fuzzing these folio functions. The `folio_may_be_lru_cached` check is a common point of interest, and these functions seem to interact with it: `collect_longterm_unpinnable_folios` in `mm/gup.c`, and the mlock functions: `mlock_folio`, `mlock_new_folio`, and `munlock_folio` from `mm/mlock.c`. I'll also bring in `__folio_batch_add_and_move` from `mm/swap.c`. These all seem like solid candidates to add to FocusSymbols. Wait a second, though... I remember that `__folio_batch_add_and_move` is declared static. That raises a flag. We need to check its callers. Static functions can be more limiting for fuzzing if their entry points are not readily available. Let's see how it's being used. I need to be sure it's worthwhile to include it and what context the fuzzing would exercise.
16/2	2026/07/10 00:27	tool	grepper	0m Args: { "Expression": "__folio_batch_add_and_move" } Results: { "Output": "mm/swap.c=158=static void folio_batch_move_lru(struct folio_batch fbatch, move_fn_t move_fn)\n--\nmm/swap.c-216-\nmm/swap.c:217:static void __folio_batch_add_and_move(struct folio_batch __percpu fbatch,\nmm/swap.c-218-\t\tstruct folio *folio, move_fn_t move_fn, bool disable_irq)\n--\nmm/swap.c-239-#define folio_batch_add_and_move(folio, op)\t\t\\\nmm/swap.c:240:\t__folio_batch_add_and_move(\t\t\t\\\nmm/swap.c-241-\t\t\u0026cpu_fbatches.op,\t\t\t\\\n" }
17/2	2026/07/10 00:27	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 13463 output: 23 thoughts: 25 Thoughts: Here's a summary of my thought process, as requested: Tracing Macro Usage Okay, so `folio_batch_add_and_move`. That's a macro. I'm going to want to understand its impact and behavior, and to do that effectively, I need to know where it's being used. Time to start tracking down its invocations. Let's see where this macro is actually called. Gotta understand the contexts!
18/2	2026/07/10 00:27	tool	grepper	0m Args: { "Expression": "folio_batch_add_and_move" } Results: { "Output": "mm/swap.c=158=static void folio_batch_move_lru(struct folio_batch fbatch, move_fn_t move_fn)\n--\nmm/swap.c-216-\nmm/swap.c:217:static void __folio_batch_add_and_move(struct folio_batch __percpu fbatch,\nmm/swap.c-218-\t\tstruct folio folio, move_fn_t move_fn, bool disable_irq)\n--\nmm/swap.c-238-\nmm/swap.c:239:#define folio_batch_add_and_move(folio, op)\t\t\\\nmm/swap.c:240:\t__folio_batch_add_and_move(\t\t\t\\\nmm/swap.c-241-\t\t\u0026cpu_fbatches.op,\t\t\t\\\n--\nmm/swap.c=266=void folio_rotate_reclaimable(struct folio folio)\n--\nmm/swap.c-271-\nmm/swap.c:272:\tfolio_batch_add_and_move(folio, lru_move_tail);\nmm/swap.c-273-}\n--\nmm/swap.c=368=void folio_activate(struct folio folio)\n--\nmm/swap.c-373-\nmm/swap.c:374:\tfolio_batch_add_and_move(folio, lru_activate);\nmm/swap.c-375-}\n--\nmm/swap.c=541=void folio_add_lru(struct folio folio)\n--\nmm/swap.c-561-\nmm/swap.c:562:\tfolio_batch_add_and_move(folio, lru_add);\nmm/swap.c-563-}\n--\nmm/swap.c=737=void deactivate_file_folio(struct folio folio)\n--\nmm/swap.c-745-\nmm/swap.c:746:\tfolio_batch_add_and_move(folio, lru_deactivate_file);\nmm/swap.c-747-}\n--\nmm/swap.c=757=void folio_deactivate(struct folio folio)\n--\nmm/swap.c-764-\nmm/swap.c:765:\tfolio_batch_add_and_move(folio, lru_deactivate);\nmm/swap.c-766-}\n--\nmm/swap.c=775=void folio_mark_lazyfree(struct folio *folio)\n--\nmm/swap.c-781-\nmm/swap.c:782:\tfolio_batch_add_and_move(folio, lru_lazyfree);\nmm/swap.c-783-}\n" }
19/2	2026/07/10 00:28	llm	patch-evaluator	0m Model: gemini-3.1-pro-preview Args: null Results: null Tokens: input: 14303 output: 232 thoughts: 429 Thoughts: My Analysis of Focus Symbols and Reasoning for Fuzzing Alright, let's break this down. My primary concern here is the memory management subsystem, specifically around folio caching and large anonymous folio reuse. I'm going to add a list of functions to FocusSymbols: `folio_rotate_reclaimable`, `folio_activate`, `folio_add_lru`, `deactivate_file_folio`, `folio_deactivate`, and `folio_mark_lazyfree`, instead of the one function, `__folio_batch_add_and_move`. Now, about `__wp_can_reuse_large_anon_folio`. It's static, which initially gave me pause. I know syzkaller can handle static functions within the kernel image, but providing the caller is always preferred, especially with inline functions. However, this one is not inline, so we are good. So, let's summarize the functions I've identified as critical for focused fuzzing: * `__wp_can_reuse_large_anon_folio` * `collect_longterm_unpinnable_folios` * `mlock_folio` * `mlock_new_folio` * `munlock_folio` * `folio_rotate_reclaimable` * `folio_activate` * `folio_add_lru` * `deactivate_file_folio` * `folio_deactivate` * `folio_mark_lazyfree` These functions encompass the areas where `folio_may_be_lru_cached` is used and also the changes to `__wp_can_reuse_large_anon_folio`. The changes touch on core memory management functions and write fault handling which is a critical area for regression testing and stability. I will also note that `TRANSPARENT_HUGEPAGE` is the relevant config. Ultimately, these are functional changes affecting core memory management and page fault handling. Therefore, fuzzing these functions is essential to ensure we don't introduce regressions or subtle bugs. I should call `set-results`.
20/2	2026/07/10 00:28	tool	set-results	0m Args: { "EnableConfigs": [ "TRANSPARENT_HUGEPAGE" ], "FocusSymbols": [ "__wp_can_reuse_large_anon_folio", "collect_longterm_unpinnable_folios", "mlock_folio", "mlock_new_folio", "munlock_folio", "folio_rotate_reclaimable", "folio_activate", "folio_add_lru", "deactivate_file_folio", "folio_deactivate", "folio_mark_lazyfree" ], "Reasoning": "The patch modifies the memory management subsystem, specifically the condition for caching folios in the per-CPU LRU cache (`folio_may_be_lru_cached`) and the logic for reusing large anonymous folios during write faults (`__wp_can_reuse_large_anon_folio`). These are functional changes that affect core memory management and page fault handling, which should be fuzzed to ensure no regressions or bugs are introduced.", "WorthFuzzing": true } Results: { "EnableConfigs": [ "TRANSPARENT_HUGEPAGE" ], "FocusSymbols": [ "__wp_can_reuse_large_anon_folio", "collect_longterm_unpinnable_folios", "mlock_folio", "mlock_new_folio", "munlock_folio", "folio_rotate_reclaimable", "folio_activate", "folio_add_lru", "deactivate_file_folio", "folio_deactivate", "folio_mark_lazyfree" ], "Reasoning": "The patch modifies the memory management subsystem, specifically the condition for caching folios in the per-CPU LRU cache (`folio_may_be_lru_cached`) and the logic for reusing large anonymous folios during write faults (`__wp_can_reuse_large_anon_folio`). These are functional changes that affect core memory management and page fault handling, which should be fuzzed to ensure no regressions or bugs are introduced.", "WorthFuzzing": true }

{
  "EnableConfigs": [
    "TRANSPARENT_HUGEPAGE"
  ],
  "FocusSymbols": [
    "__wp_can_reuse_large_anon_folio",
    "collect_longterm_unpinnable_folios",
    "mlock_folio",
    "mlock_new_folio",
    "munlock_folio",
    "folio_rotate_reclaimable",
    "folio_activate",
    "folio_add_lru",
    "deactivate_file_folio",
    "folio_deactivate",
    "folio_mark_lazyfree"
  ],
  "Reasoning": "The patch modifies the memory management subsystem, specifically the condition for caching folios in the per-CPU LRU cache (`folio_may_be_lru_cached`) and the logic for reusing large anonymous folios during write faults (`__wp_can_reuse_large_anon_folio`). These are functional changes that affect core memory management and page fault handling, which should be fuzzed to ensure no regressions or bugs are introduced.",
  "WorthFuzzing": true
}

{
  "PatchDiff": "commit 0cf8ce242fbe6debed46cbfa0be767677f7b7b32\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate:   Fri Jul 10 00:26:56 2026 +0000\n\n    syz-cluster: applied patch under review\n\ndiff --git a/include/linux/swap.h b/include/linux/swap.h\nindex 8f0f68e245baa3..fce1d84aa2c818 100644\n--- a/include/linux/swap.h\n+++ b/include/linux/swap.h\n@@ -322,9 +322,9 @@ static inline bool folio_may_be_lru_cached(struct folio *folio)\n \t/*\n \t * Holding PMD-sized folios in per-CPU LRU cache unbalances accounting.\n \t * Holding small numbers of low-order mTHP folios in per-CPU LRU cache\n-\t * will be sensible, but nobody has implemented and tested that yet.\n+\t * will be sensible.\n \t */\n-\treturn !folio_test_large(folio);\n+\treturn folio_order(folio) \u003c PAGE_ALLOC_COSTLY_ORDER;\n }\n \n extern atomic_t lru_disable_count;\ndiff --git a/mm/memory.c b/mm/memory.c\nindex ff338c2abe9231..8572228743b2e3 100644\n--- a/mm/memory.c\n+++ b/mm/memory.c\n@@ -4143,6 +4143,19 @@ static bool __wp_can_reuse_large_anon_folio(struct folio *folio,\n \t\tfolio_unlock(folio);\n \t}\n \n+\tif (folio_may_be_lru_cached(folio) \u0026\u0026 !folio_test_lru(folio)) {\n+\t\tif (folio_ref_count(folio) \u003e folio_large_mapcount(folio) + 1)\n+\t\t\treturn false;\n+\t\t/*\n+\t\t * A global LRU drain is too expensive, but a local drain\n+\t\t * can still be beneficial. For example, large folios that\n+\t\t * have just been swapped in and fall back from\n+\t\t * do_swap_page() to do_wp_page() are likely still in this\n+\t\t * CPU's LRU cache.\n+\t\t */\n+\t\tlru_add_drain();\n+\t}\n+\n \tif (folio_large_mapcount(folio) != folio_ref_count(folio))\n \t\treturn false;\n \n"
}

gemini-3.1-pro-preview

{
  "EnableConfigs": [
    "TRANSPARENT_HUGEPAGE"
  ],
  "FocusSymbols": [
    "__wp_can_reuse_large_anon_folio",
    "collect_longterm_unpinnable_folios",
    "mlock_folio",
    "mlock_new_folio",
    "munlock_folio",
    "folio_rotate_reclaimable",
    "folio_activate",
    "folio_add_lru",
    "deactivate_file_folio",
    "folio_deactivate",
    "folio_mark_lazyfree"
  ],
  "Reasoning": "The patch modifies the memory management subsystem, specifically the condition for caching folios in the per-CPU LRU cache (`folio_may_be_lru_cached`) and the logic for reusing large anonymous folios during write faults (`__wp_can_reuse_large_anon_folio`). These are functional changes that affect core memory management and page fault handling, which should be fuzzed to ensure no regressions or bugs are introduced.",
  "WorthFuzzing": true
}

You are an expert Linux kernel maintainer.
Your job is to review a provided patch series and determine
if it makes functional changes to the kernel that should be fuzzed.

IMPORTANT: The changes have ALREADY been applied and committed as the HEAD commit in
your workspace. Do NOT rely on your internal knowledge of the kernel. You must actively
use your code access tools to examine the actual source code and confirm any assumptions.

Return WorthFuzzing=false if the patch only contains:
- Modifications to Documentation/, Kconfig files, or code comments.
- Purely decorative changes, such as logging (e.g., pr_err, printk) or tracepoints.
- Changes to numeric constants or macros that do not functionally alter execution flow.
- Code paths that are impossible to reach in virtualized environments like GCE or QEMU,
even when utilizing software-emulated hardware (e.g., usb gadget, mac80211_hwsim).

If it modifies reachable core kernel logic, drivers, or architectures, use your code search
tools to verify the code can be executed, then return WorthFuzzing=true.

When returning WorthFuzzing=true, you MUST ALSO:
1. Extract any specific kernel functions that should be heavily fuzzed into FocusSymbols.
   Avoid listing generic hot-path functions to prevent skewed test distributions.
2. Identify any specific CONFIG_ options required to properly test this new/modified feature.
   Go and look into the Kconfig files and check for ifdefs around the code, do not make assumptions.
   Do not list too generic configs (we already have them enabled). Only list those that
   specifically cover the modified code. List them in the EnableConfigs output array,
   and DO NOT add a '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.

For your convenience, here is the diff of the changes:
commit 0cf8ce242fbe6debed46cbfa0be767677f7b7b32
Author: syz-cluster <triage@syzkaller.com>
Date:   Fri Jul 10 00:26:56 2026 +0000

    syz-cluster: applied patch under review

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 8f0f68e245baa3..fce1d84aa2c818 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -322,9 +322,9 @@ static inline bool folio_may_be_lru_cached(struct folio *folio)
 	/*
 	 * Holding PMD-sized folios in per-CPU LRU cache unbalances accounting.
 	 * Holding small numbers of low-order mTHP folios in per-CPU LRU cache
-	 * will be sensible, but nobody has implemented and tested that yet.
+	 * will be sensible.
 	 */
-	return !folio_test_large(folio);
+	return folio_order(folio) < PAGE_ALLOC_COSTLY_ORDER;
 }
 
 extern atomic_t lru_disable_count;
diff --git a/mm/memory.c b/mm/memory.c
index ff338c2abe9231..8572228743b2e3 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4143,6 +4143,19 @@ static bool __wp_can_reuse_large_anon_folio(struct folio *folio,
 		folio_unlock(folio);
 	}
 
+	if (folio_may_be_lru_cached(folio) && !folio_test_lru(folio)) {
+		if (folio_ref_count(folio) > folio_large_mapcount(folio) + 1)
+			return false;
+		/*
+		 * A global LRU drain is too expensive, but a local drain
+		 * can still be beneficial. For example, large folios that
+		 * have just been swapped in and fall back from
+		 * do_swap_page() to do_wp_page() are likely still in this
+		 * CPU's LRU cache.
+		 */
+		lru_add_drain();
+	}
+
 	if (folio_large_mapcount(folio) != folio_ref_count(folio))
 		return false;

gemini-3.1-pro-preview

							input: 2180
							output: 26
							thoughts: 311

**Analyzing a Recent Swap Patch**

Okay, so I'm looking at this patch and it seems like it's a relatively focused change within the memory management subsystem, specifically concerning how we handle large anonymous folios during write faults. The core of the change lies in a couple of key modifications.

First, they've altered `folio_may_be_lru_cached` in `include/linux/swap.h`. Previously, it was checking if a folio *wasn't* large using `!folio_test_large(folio)`. Now, it's checking if the folio's order is less than `PAGE_ALLOC_COSTLY_ORDER`. This subtly shifts the definition of what we consider eligible for LRU caching. I need to think about the implications here. Are there scenarios where this new check might lead to different behavior, perhaps more or fewer folios being considered for LRU? I'll have to investigate that further, thinking about the performance ramifications, especially around swapping.

Then, the second part of the change introduces new logic inside `__wp_can_reuse_large_anon_folio` in `mm/memory.c`. It adds a conditional check that now includes this new `folio_may_be_lru_cached` criterion, plus a further condition that the folio is *not* currently on the LRU (`!folio_test_lru(folio)`).

What really catches my eye is this `if` block. It seems to be trying to improve large anonymous folio reuse in scenarios where they're recently swapped in. If the folio is a candidate for the LRU, but not *actually* on it, the code attempts to drain the LRU. This is likely to prevent the costly global LRU drain. The comment hints at optimizations to improve the likelihood of reuse for folios that were recently swapped in.

So, in essence, this is a functional modification aimed at improving write fault performance, particularly when large anonymous folios are involved. It's about making smarter decisions about when to reuse these large folios, potentially reducing page faults and improving overall system responsiveness. I want to delve deeper into the rationale for this, and see if it is going to cause any regressions, or conflicts.

{
  "Expression": "__wp_can_reuse_large_anon_folio"
}

{
  "Output": "mm/memory.c=4067=static vm_fault_t wp_page_shared(struct vm_fault *vmf, struct folio *folio)\n--\nmm/memory.c-4107-#ifdef CONFIG_TRANSPARENT_HUGEPAGE\nmm/memory.c:4108:static bool __wp_can_reuse_large_anon_folio(struct folio *folio,\nmm/memory.c-4109-\t\tstruct vm_area_struct *vma)\n--\nmm/memory.c-4186-#else /* !CONFIG_TRANSPARENT_HUGEPAGE */\nmm/memory.c:4187:static bool __wp_can_reuse_large_anon_folio(struct folio *folio,\nmm/memory.c-4188-\t\tstruct vm_area_struct *vma)\n--\nmm/memory.c=4194=static bool wp_can_reuse_anon_folio(struct folio *folio,\n--\nmm/memory.c-4197-\tif (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) \u0026\u0026 folio_test_large(folio))\nmm/memory.c:4198:\t\treturn __wp_can_reuse_large_anon_folio(folio, vma);\nmm/memory.c-4199-\n"
}

gemini-3.1-pro-preview

							input: 3315
							output: 24
							thoughts: 66

Okay, let's break this down.

**Understanding Folio Reusability with Transparent Hugepages**

Alright, so the function `__wp_can_reuse_large_anon_folio`... that's exclusively defined under the `CONFIG_TRANSPARENT_HUGEPAGE` conditional. That immediately tells me that Transparent Hugepages are a hard requirement for this function to even exist. Without that configuration, this code path is simply not compiled, making the function irrelevant. This is a crucial dependency to remember when considering how the overall memory management system behaves. It's a key piece in the puzzle of large page optimization, so I need to keep that in mind.

Now, my next question is regarding its interaction with other processes, let's explore `folio_may_be_lru_cached`.

{
  "Expression": "folio_may_be_lru_cached"
}

{
  "Output": "include/linux/swap.h=318=void folio_mark_accessed(struct folio *);\ninclude/linux/swap.h-319-\ninclude/linux/swap.h:320:static inline bool folio_may_be_lru_cached(struct folio *folio)\ninclude/linux/swap.h-321-{\n--\nmm/gup.c=2265=static unsigned long collect_longterm_unpinnable_folios(\n--\nmm/gup.c-2289-\nmm/gup.c:2290:\t\tif (drained == 0 \u0026\u0026 folio_may_be_lru_cached(folio) \u0026\u0026\nmm/gup.c-2291-\t\t\t\tfolio_ref_count(folio) !=\n--\nmm/gup.c-2295-\t\t}\nmm/gup.c:2296:\t\tif (drained == 1 \u0026\u0026 folio_may_be_lru_cached(folio) \u0026\u0026\nmm/gup.c-2297-\t\t\t\tfolio_ref_count(folio) !=\n--\nmm/memory.c=4108=static bool __wp_can_reuse_large_anon_folio(struct folio *folio,\n--\nmm/memory.c-4145-\nmm/memory.c:4146:\tif (folio_may_be_lru_cached(folio) \u0026\u0026 !folio_test_lru(folio)) {\nmm/memory.c-4147-\t\tif (folio_ref_count(folio) \u003e folio_large_mapcount(folio) + 1)\n--\nmm/mlock.c=242=void mlock_folio(struct folio *folio)\n--\nmm/mlock.c-257-\tif (!folio_batch_add(fbatch, mlock_lru(folio)) ||\nmm/mlock.c:258:\t    !folio_may_be_lru_cached(folio) || lru_cache_disabled())\nmm/mlock.c-259-\t\tmlock_folio_batch(fbatch);\n--\nmm/mlock.c=267=void mlock_new_folio(struct folio *folio)\n--\nmm/mlock.c-280-\tif (!folio_batch_add(fbatch, mlock_new(folio)) ||\nmm/mlock.c:281:\t    !folio_may_be_lru_cached(folio) || lru_cache_disabled())\nmm/mlock.c-282-\t\tmlock_folio_batch(fbatch);\n--\nmm/mlock.c=290=void munlock_folio(struct folio *folio)\n--\nmm/mlock.c-301-\tif (!folio_batch_add(fbatch, folio) ||\nmm/mlock.c:302:\t    !folio_may_be_lru_cached(folio) || lru_cache_disabled())\nmm/mlock.c-303-\t\tmlock_folio_batch(fbatch);\n--\nmm/swap.c=217=static void __folio_batch_add_and_move(struct folio_batch __percpu *fbatch,\n--\nmm/swap.c-229-\tif (!folio_batch_add(this_cpu_ptr(fbatch), folio) ||\nmm/swap.c:230:\t\t\t!folio_may_be_lru_cached(folio) || lru_cache_disabled())\nmm/swap.c-231-\t\tfolio_batch_move_lru(this_cpu_ptr(fbatch), move_fn);\n"
}

gemini-3.1-pro-preview

							input: 4465
							output: 23
							thoughts: 147

**Analyzing the Memory Management Patch**

Okay, so this patch is definitely working as intended. I see it's dealing with memory management, specifically how those large, anonymous folios are handled when a write fault occurs. It's also touching the logic around `folio_may_be_lru_cached`.

Let's see, which symbols should I focus on? `__wp_can_reuse_large_anon_folio` looks like a good starting point. I know `folio_may_be_lru_cached` is an inline function, so it's not a symbol I can just jump to. Ah, right, `wp_can_reuse_anon_folio` is the caller of that inline function. And, since we're talking about write faults, `do_wp_page` is the caller of *that* function.

Alright, I'll start with digging into `wp_can_reuse_anon_folio` and see what's going on.

{
  "Expression": "wp_can_reuse_anon_folio"
}

{
  "Output": "mm/memory.c=4187=static bool __wp_can_reuse_large_anon_folio(struct folio *folio,\n--\nmm/memory.c-4193-\nmm/memory.c:4194:static bool wp_can_reuse_anon_folio(struct folio *folio,\nmm/memory.c-4195-\t\t\t\t    struct vm_area_struct *vma)\n--\nmm/memory.c=4257=static vm_fault_t do_wp_page(struct vm_fault *vmf)\n--\nmm/memory.c-4327-\tif (folio \u0026\u0026 folio_test_anon(folio) \u0026\u0026\nmm/memory.c:4328:\t    (PageAnonExclusive(vmf-\u003epage) || wp_can_reuse_anon_folio(folio, vma))) {\nmm/memory.c-4329-\t\tif (!PageAnonExclusive(vmf-\u003epage))\n"
}

gemini-3.1-pro-preview

							input: 5084
							output: 22
							thoughts: 127

**Analyzing Memory Re-use Paths**

Okay, so `do_wp_page` is definitely a performance bottleneck, a hot path as they say, but I think focusing on `__wp_can_reuse_large_anon_folio` might be more productive right now. It's a more targeted function. I'm going to use that as my primary focus.

First, let's verify the setup. I already know that `TRANSPARENT_HUGEPAGE` is a hard requirement for `__wp_can_reuse_large_anon_folio` to even be relevant. I need to keep that in mind.

Now, let me see if there are other relevant configurations. Ah, here's one: `PAGE_ALLOC_COSTLY_ORDER`. I see it's used within `folio_may_be_lru_cached`. It looks like it's just a constant, but its context could be crucial to determining why certain re-use pathways might be more optimal than others. I'll need to dig into how this value impacts allocation.

{
  "Expression": "PAGE_ALLOC_COSTLY_ORDER"
}

{
  "Output": "Documentation/admin-guide/mm/slab.rst=150=can be influenced by kernel parameters:\n--\nDocumentation/admin-guide/mm/slab.rst-153-.. slab_min_order=x\t\t(default 0)\nDocumentation/admin-guide/mm/slab.rst:154:.. slab_max_order=x\t\t(default 3 (PAGE_ALLOC_COSTLY_ORDER))\nDocumentation/admin-guide/mm/slab.rst-155-\n--\ndrivers/net/ethernet/amd/xgbe/xgbe-desc.c=247=static int xgbe_map_rx_buffer(struct xgbe_prv_data *pdata,\n--\ndrivers/net/ethernet/amd/xgbe/xgbe-desc.c-260-\t\tret = xgbe_alloc_pages(pdata, \u0026ring-\u003erx_buf_pa,\ndrivers/net/ethernet/amd/xgbe/xgbe-desc.c:261:\t\t\t\t       PAGE_ALLOC_COSTLY_ORDER, ring-\u003enode);\ndrivers/net/ethernet/amd/xgbe/xgbe-desc.c-262-\t\tif (ret)\n--\ndrivers/net/ethernet/synopsys/dwc-xlgmac-desc.c=385=static int xlgmac_map_rx_buffer(struct xlgmac_pdata *pdata,\n--\ndrivers/net/ethernet/synopsys/dwc-xlgmac-desc.c-398-\tif (!ring-\u003erx_buf_pa.pages) {\ndrivers/net/ethernet/synopsys/dwc-xlgmac-desc.c:399:\t\torder = max_t(int, PAGE_ALLOC_COSTLY_ORDER - 1, 0);\ndrivers/net/ethernet/synopsys/dwc-xlgmac-desc.c-400-\t\tret = xlgmac_alloc_pages(pdata, \u0026ring-\u003erx_buf_pa,\n--\ndrivers/net/tap.c=543=static inline struct sk_buff *tap_alloc_skb(struct sock *sk, size_t prepad,\n--\ndrivers/net/tap.c-552-\ndrivers/net/tap.c:553:\tif (len - linear \u003e MAX_SKB_FRAGS * (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER))\ndrivers/net/tap.c:554:\t\tlinear = len - MAX_SKB_FRAGS * (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER);\ndrivers/net/tap.c-555-\tskb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,\ndrivers/net/tap.c:556:\t\t\t\t   err, PAGE_ALLOC_COSTLY_ORDER);\ndrivers/net/tap.c-557-\tif (!skb)\n--\ndrivers/net/tun.c=1480=static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,\n--\ndrivers/net/tun.c-1491-\ndrivers/net/tun.c:1492:\tif (len - linear \u003e MAX_SKB_FRAGS * (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER))\ndrivers/net/tun.c:1493:\t\tlinear = len - MAX_SKB_FRAGS * (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER);\ndrivers/net/tun.c-1494-\tskb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,\ndrivers/net/tun.c:1495:\t\t\t\t   \u0026err, PAGE_ALLOC_COSTLY_ORDER);\ndrivers/net/tun.c-1496-\tif (!skb)\n--\nfs/fuse/file.c=2351=static void fuse_vma_close(struct vm_area_struct *vma)\n--\nfs/fuse/file.c-2371- * - sync(2)\nfs/fuse/file.c:2372: * - try_to_free_pages() with order \u003e PAGE_ALLOC_COSTLY_ORDER\nfs/fuse/file.c-2373- */\n--\nfs/gfs2/glock.c=2580=static const struct seq_operations gfs2_sbstats_sops = {\n--\nfs/gfs2/glock.c-2586-\nfs/gfs2/glock.c:2587:#define GFS2_SEQ_GOODSIZE min(PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER, 65536UL)\nfs/gfs2/glock.c-2588-\n--\ninclude/linux/gfp_types.h=26=enum {\n--\ninclude/linux/gfp_types.h-207- * The default allocator behavior depends on the request size. We have a concept\ninclude/linux/gfp_types.h:208: * of so-called costly allocations (with order \u003e %PAGE_ALLOC_COSTLY_ORDER).\ninclude/linux/gfp_types.h-209- * !costly allocations are too essential to fail so they are implicitly\n--\ninclude/linux/mmzone.h-57-/*\ninclude/linux/mmzone.h:58: * PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed\ninclude/linux/mmzone.h-59- * costly to service.  That is between allocation orders which should\n--\ninclude/linux/mmzone.h-62- */\ninclude/linux/mmzone.h:63:#define PAGE_ALLOC_COSTLY_ORDER 3\ninclude/linux/mmzone.h-64-\n--\ninclude/linux/mmzone.h=797=enum zone_watermarks {\n--\ninclude/linux/mmzone.h-805-/*\ninclude/linux/mmzone.h:806: * One per migratetype for each PAGE_ALLOC_COSTLY_ORDER. Two additional lists\ninclude/linux/mmzone.h-807- * are added for THP. One PCP list is used by GPF_MOVABLE, and the other PCP list\n--\ninclude/linux/mmzone.h-814-#endif\ninclude/linux/mmzone.h:815:#define NR_LOWORDER_PCP_LISTS (MIGRATE_PCPTYPES * (PAGE_ALLOC_COSTLY_ORDER + 1))\ninclude/linux/mmzone.h-816-#define NR_PCP_LISTS (NR_LOWORDER_PCP_LISTS + NR_PCP_THP)\n--\ninclude/linux/swap.h=320=static inline bool folio_may_be_lru_cached(struct folio *folio)\n--\ninclude/linux/swap.h-326-\t */\ninclude/linux/swap.h:327:\treturn folio_order(folio) \u003c PAGE_ALLOC_COSTLY_ORDER;\ninclude/linux/swap.h-328-}\n--\ninclude/linux/virtio_vsock.h=61=__virtio_vsock_alloc_skb_with_frags(unsigned int header_len,\n--\ninclude/linux/virtio_vsock.h-68-\tskb = alloc_skb_with_frags(header_len, data_len,\ninclude/linux/virtio_vsock.h:69:\t\t\t\t   PAGE_ALLOC_COSTLY_ORDER, \u0026err, mask);\ninclude/linux/virtio_vsock.h-70-\tif (!skb)\n--\ninclude/linux/virtio_vsock.h=84=static inline struct sk_buff *virtio_vsock_alloc_skb(unsigned int size, gfp_t mask)\ninclude/linux/virtio_vsock.h-85-{\ninclude/linux/virtio_vsock.h:86:\tif (size \u003c= SKB_WITH_OVERHEAD(PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER))\ninclude/linux/virtio_vsock.h-87-\t\treturn virtio_vsock_alloc_linear_skb(size, mask);\n--\nkernel/bpf/syscall.c=373=static void *__bpf_map_area_alloc(u64 size, int numa_node, bool mmapable)\n--\nkernel/bpf/syscall.c-397-\t\tflags = VM_USERMAP;\nkernel/bpf/syscall.c:398:\t} else if (size \u003c= (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER)) {\nkernel/bpf/syscall.c-399-\t\tarea = kmalloc_node(size, gfp | GFP_USER | __GFP_NORETRY,\n--\nmm/compaction.c=276=__reset_isolation_pfn(struct zone *zone, unsigned long pfn, bool check_source,\n--\nmm/compaction.c-337-\nmm/compaction.c:338:\t\tpage += (1 \u003c\u003c PAGE_ALLOC_COSTLY_ORDER);\nmm/compaction.c-339-\t} while (page \u003c= end_page);\n--\nmm/compaction.c=1939=static unsigned long fast_find_migrateblock(struct compact_control *cc)\n--\nmm/compaction.c-1972-\t */\nmm/compaction.c:1973:\tif (cc-\u003eorder \u003c= PAGE_ALLOC_COSTLY_ORDER)\nmm/compaction.c-1974-\t\treturn pfn;\n--\nmm/compaction.c-1996-\tfor (order = cc-\u003eorder - 1;\nmm/compaction.c:1997:\t     order \u003e= PAGE_ALLOC_COSTLY_ORDER \u0026\u0026 !found_block \u0026\u0026 nr_scanned \u003c limit;\nmm/compaction.c-1998-\t     order--) {\n--\nmm/compaction.c=2374=static bool __compaction_suitable(struct zone *zone, int order,\n--\nmm/compaction.c-2394-\twatermark += compact_gap(order);\nmm/compaction.c:2395:\tif (order \u003e PAGE_ALLOC_COSTLY_ORDER)\nmm/compaction.c-2396-\t\twatermark += low_wmark_pages(zone) - min_wmark_pages(zone);\n--\nmm/compaction.c=2404=bool compaction_suitable(struct zone *zone, int order, unsigned long watermark,\n--\nmm/compaction.c-2429-\t\tcompact_result = COMPACT_CONTINUE;\nmm/compaction.c:2430:\t\tif (order \u003e PAGE_ALLOC_COSTLY_ORDER) {\nmm/compaction.c-2431-\t\t\tint fragindex = fragmentation_index(zone, order);\n--\nmm/compaction.c=2491=compaction_suit_allocation_order(struct zone *zone, unsigned int order,\n--\nmm/compaction.c-2516-\t */\nmm/compaction.c:2517:\tif (order \u003e PAGE_ALLOC_COSTLY_ORDER \u0026\u0026 async \u0026\u0026\nmm/compaction.c-2518-\t    !(alloc_flags \u0026 ALLOC_CMA)) {\n--\nmm/kasan/hw_tags.c=73=unsigned long kasan_page_alloc_sample = PAGE_ALLOC_SAMPLE_DEFAULT;\n--\nmm/kasan/hw_tags.c-77- * The default value is chosen to match both\nmm/kasan/hw_tags.c:78: * PAGE_ALLOC_COSTLY_ORDER and SKB_FRAG_PAGE_ORDER.\nmm/kasan/hw_tags.c-79- */\n--\nmm/memcontrol.c=1918=static bool mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)\n--\nmm/memcontrol.c-1921-\nmm/memcontrol.c:1922:\tif (order \u003e PAGE_ALLOC_COSTLY_ORDER)\nmm/memcontrol.c-1923-\t\treturn false;\n--\nmm/memcontrol.c=2595=static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,\n--\nmm/memcontrol.c-2678-\t */\nmm/memcontrol.c:2679:\tif (nr_reclaimed \u0026\u0026 nr_pages \u003c= (1 \u003c\u003c PAGE_ALLOC_COSTLY_ORDER))\nmm/memcontrol.c-2680-\t\tgoto retry;\n--\nmm/page_alloc.c=651=static inline unsigned int order_to_pindex(int migratetype, int order)\n--\nmm/page_alloc.c-655-\nmm/page_alloc.c:656:\t\tif (order \u003e PAGE_ALLOC_COSTLY_ORDER)\nmm/page_alloc.c-657-\t\t\treturn NR_LOWORDER_PCP_LISTS + movable;\n--\nmm/page_alloc.c=675=static inline bool pcp_allowed_order(unsigned int order)\nmm/page_alloc.c-676-{\nmm/page_alloc.c:677:\tif (order \u003c= PAGE_ALLOC_COSTLY_ORDER)\nmm/page_alloc.c-678-\t\treturn true;\n--\nmm/page_alloc.c=2832=static bool free_frozen_page_commit(struct zone *zone,\n--\nmm/page_alloc.c-2860-\t */\nmm/page_alloc.c:2861:\tif (order \u0026\u0026 order \u003c= PAGE_ALLOC_COSTLY_ORDER) {\nmm/page_alloc.c-2862-\t\tfree_high = (pcp-\u003efree_count \u003e= (batch + pcp-\u003ehigh_min / 2) \u0026\u0026\n--\nmm/page_alloc.c=4047=__alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,\n--\nmm/page_alloc.c-4087-\t/* The OOM killer will not help higher order allocs */\nmm/page_alloc.c:4088:\tif (order \u003e PAGE_ALLOC_COSTLY_ORDER)\nmm/page_alloc.c-4089-\t\tgoto out;\n--\nmm/page_alloc.c=4202=should_compact_retry(gfp_t gfp_mask, struct alloc_context *ac, int order,\n--\nmm/page_alloc.c-4243-\t\t */\nmm/page_alloc.c:4244:\t\tif (order \u003e PAGE_ALLOC_COSTLY_ORDER)\nmm/page_alloc.c-4245-\t\t\tmax_retries /= 4;\n--\nmm/page_alloc.c-4255-\t */\nmm/page_alloc.c:4256:\tmin_priority = (order \u003e PAGE_ALLOC_COSTLY_ORDER) ?\nmm/page_alloc.c-4257-\t\t\tMIN_COMPACT_COSTLY_PRIORITY : MIN_COMPACT_PRIORITY;\n--\nmm/page_alloc.c=4279=should_compact_retry(gfp_t gfp_mask, struct alloc_context *ac, int order,\n--\nmm/page_alloc.c-4287-\nmm/page_alloc.c:4288:\tif (!order || order \u003e PAGE_ALLOC_COSTLY_ORDER)\nmm/page_alloc.c-4289-\t\treturn false;\n--\nmm/page_alloc.c=4581=should_reclaim_retry(gfp_t gfp_mask, unsigned order,\n--\nmm/page_alloc.c-4593-\t */\nmm/page_alloc.c:4594:\tif (did_some_progress \u0026\u0026 order \u003c= PAGE_ALLOC_COSTLY_ORDER)\nmm/page_alloc.c-4595-\t\t*no_progress_loops = 0;\n--\nmm/page_alloc.c=4725=__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,\n--\nmm/page_alloc.c-4730-\tbool nofail = gfp_mask \u0026 __GFP_NOFAIL;\nmm/page_alloc.c:4731:\tconst bool costly_order = order \u003e PAGE_ALLOC_COSTLY_ORDER;\nmm/page_alloc.c-4732-\tstruct page *page = NULL;\n--\nmm/slub.c=7487=static unsigned int slub_max_order =\nmm/slub.c:7488:\tIS_ENABLED(CONFIG_SLUB_TINY) ? 1 : PAGE_ALLOC_COSTLY_ORDER;\nmm/slub.c-7489-static unsigned int slub_min_objects;\n--\nmm/vmpressure.c=240=void vmpressure(gfp_t gfp, int order, struct mem_cgroup *memcg, bool tree,\n--\nmm/vmpressure.c-318-\t\t */\nmm/vmpressure.c:319:\t\tif (level \u003e VMPRESSURE_LOW \u0026\u0026 order \u003c= PAGE_ALLOC_COSTLY_ORDER) {\nmm/vmpressure.c-320-\t\t\t/*\n--\nmm/vmscan.c=5998=static bool in_reclaim_compaction(struct scan_control *sc)\n--\nmm/vmscan.c-6000-\tif (gfp_compaction_allowed(sc-\u003egfp_mask) \u0026\u0026 sc-\u003eorder \u0026\u0026\nmm/vmscan.c:6001:\t\t\t(sc-\u003eorder \u003e PAGE_ALLOC_COSTLY_ORDER ||\nmm/vmscan.c-6002-\t\t\t sc-\u003epriority \u003c DEF_PRIORITY - 2))\n--\nmm/vmscan.c=6331=static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc)\n--\nmm/vmscan.c-6372-\t\t\tif (IS_ENABLED(CONFIG_COMPACTION) \u0026\u0026\nmm/vmscan.c:6373:\t\t\t    sc-\u003eorder \u003e PAGE_ALLOC_COSTLY_ORDER \u0026\u0026\nmm/vmscan.c-6374-\t\t\t    compaction_ready(zone, sc)) {\n--\nnet/core/net-sysfs.c=1067=static ssize_t store_rps_dev_flow_table_cnt(struct netdev_rx_queue *queue,\n--\nnet/core/net-sysfs.c-1096-\t\t\t   PAGE_SIZE);\nnet/core/net-sysfs.c:1097:\t\tif (sz \u003c= (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER) ||\nnet/core/net-sysfs.c-1098-\t\t    is_power_of_2(sizeof(*table)))\n--\nnet/ipv4/tcp_input.c=5519=int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size)\n--\nnet/ipv4/tcp_input.c-5535-\tskb = alloc_skb_with_frags(size - data_len, data_len,\nnet/ipv4/tcp_input.c:5536:\t\t\t\t   PAGE_ALLOC_COSTLY_ORDER,\nnet/ipv4/tcp_input.c-5537-\t\t\t\t   \u0026err, sk-\u003esk_allocation);\n--\nnet/packet/af_packet.c=2919=static struct sk_buff *packet_alloc_skb(struct sock *sk, size_t prepad,\n--\nnet/packet/af_packet.c-2929-\nnet/packet/af_packet.c:2930:\tif (len - linear \u003e MAX_SKB_FRAGS * (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER))\nnet/packet/af_packet.c:2931:\t\tlinear = len - MAX_SKB_FRAGS * (PAGE_SIZE \u003c\u003c PAGE_ALLOC_COSTLY_ORDER);\nnet/packet/af_packet.c-2932-\tskb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,\nnet/packet/af_packet.c:2933:\t\t\t\t   err, PAGE_ALLOC_COSTLY_ORDER);\nnet/packet/af_packet.c-2934-\tif (!skb)\n--\nnet/tls/tls.h-43-\nnet/tls/tls.h:44:#define TLS_PAGE_ORDER\t(min_t(unsigned int, PAGE_ALLOC_COSTLY_ORDER,\t\\\nnet/tls/tls.h-45-\t\t\t       TLS_MAX_PAYLOAD_SIZE \u003e\u003e PAGE_SHIFT))\n--\nnet/unix/af_unix.c=2082=static int unix_dgram_sendmsg(struct socket *sock, struct msghdr *msg,\n--\nnet/unix/af_unix.c-2137-\t\t\t\t   msg-\u003emsg_flags \u0026 MSG_DONTWAIT, \u0026err,\nnet/unix/af_unix.c:2138:\t\t\t\t   PAGE_ALLOC_COSTLY_ORDER);\nnet/unix/af_unix.c-2139-\tif (!skb)\n--\ntools/include/linux/gfp_types.h=26=enum {\n--\ntools/include/linux/gfp_types.h-207- * The default allocator behavior depends on the request size. We have a concept\ntools/include/linux/gfp_types.h:208: * of so-called costly allocations (with order \u003e %PAGE_ALLOC_COSTLY_ORDER).\ntools/include/linux/gfp_types.h-209- * !costly allocations are too essential to fail so they are implicitly\n"
}

gemini-3.1-pro-preview

							input: 10802
							output: 26
							thoughts: 199

**Analyzing the Configuration Dependencies for a Kernel Patch**

Okay, so I'm looking at this kernel patch and figuring out its configuration requirements. The macro `PAGE_ALLOC_COSTLY_ORDER` is defined as `3` in `include/linux/mmzone.h`. Since it's a hardcoded value, there's no specific configuration knob I need to worry about for it. Good, that simplifies things.

The real focus here is on `TRANSPARENT_HUGEPAGE`, it seems. That's the only config that really matters, and I want to confirm that. Let's see... the code's touching `folio_may_be_lru_cached`, and I know that function is used across a number of key memory management files: `mm/gup.c`, `mm/memory.c`, `mm/mlock.c`, and `mm/swap.c`. These are core components, so any dependencies there are critical to understand.

This patch, in particular, is changing `__wp_can_reuse_large_anon_folio`, which is *guarded* by `CONFIG_TRANSPARENT_HUGEPAGE`. That's a strong indicator. It confirms that `TRANSPARENT_HUGEPAGE` is the only explicit dependency.

Just to be absolutely sure, I'm going to take a closer look at `mm/memory.c` one more time. I've got a good mental map of this code, but it's always worth a quick scan to make sure there aren't any subtle, easily-missed configs lurking in there. Better safe than sorry.

{
  "Expression": "__wp_can_reuse_large_anon_folio"
}

{
  "Output": "mm/memory.c=4067=static vm_fault_t wp_page_shared(struct vm_fault *vmf, struct folio *folio)\n--\nmm/memory.c-4107-#ifdef CONFIG_TRANSPARENT_HUGEPAGE\nmm/memory.c:4108:static bool __wp_can_reuse_large_anon_folio(struct folio *folio,\nmm/memory.c-4109-\t\tstruct vm_area_struct *vma)\n--\nmm/memory.c-4186-#else /* !CONFIG_TRANSPARENT_HUGEPAGE */\nmm/memory.c:4187:static bool __wp_can_reuse_large_anon_folio(struct folio *folio,\nmm/memory.c-4188-\t\tstruct vm_area_struct *vma)\n--\nmm/memory.c=4194=static bool wp_can_reuse_anon_folio(struct folio *folio,\n--\nmm/memory.c-4197-\tif (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) \u0026\u0026 folio_test_large(folio))\nmm/memory.c:4198:\t\treturn __wp_can_reuse_large_anon_folio(folio, vma);\nmm/memory.c-4199-\n"
}

gemini-3.1-pro-preview

							input: 11705
							output: 24
							thoughts: 50

Okay, here's my take on those thoughts, framed as my own:

**Digging into THP Cache Optimization**

Right, *CONFIG_TRANSPARENT_HUGEPAGE*... that's the key. That's the one we're interested in for our current line of inquiry. Now, let's see if we can identify other interesting locations to focus on.

Let's see where the function *folio_may_be_lru_cached* is used. Are there other uses of that function that we can make note of, and use as focus symbols for the study?

{
  "Expression": "folio_may_be_lru_cached"
}

{
  "Output": "include/linux/swap.h=318=void folio_mark_accessed(struct folio *);\ninclude/linux/swap.h-319-\ninclude/linux/swap.h:320:static inline bool folio_may_be_lru_cached(struct folio *folio)\ninclude/linux/swap.h-321-{\n--\nmm/gup.c=2265=static unsigned long collect_longterm_unpinnable_folios(\n--\nmm/gup.c-2289-\nmm/gup.c:2290:\t\tif (drained == 0 \u0026\u0026 folio_may_be_lru_cached(folio) \u0026\u0026\nmm/gup.c-2291-\t\t\t\tfolio_ref_count(folio) !=\n--\nmm/gup.c-2295-\t\t}\nmm/gup.c:2296:\t\tif (drained == 1 \u0026\u0026 folio_may_be_lru_cached(folio) \u0026\u0026\nmm/gup.c-2297-\t\t\t\tfolio_ref_count(folio) !=\n--\nmm/memory.c=4108=static bool __wp_can_reuse_large_anon_folio(struct folio *folio,\n--\nmm/memory.c-4145-\nmm/memory.c:4146:\tif (folio_may_be_lru_cached(folio) \u0026\u0026 !folio_test_lru(folio)) {\nmm/memory.c-4147-\t\tif (folio_ref_count(folio) \u003e folio_large_mapcount(folio) + 1)\n--\nmm/mlock.c=242=void mlock_folio(struct folio *folio)\n--\nmm/mlock.c-257-\tif (!folio_batch_add(fbatch, mlock_lru(folio)) ||\nmm/mlock.c:258:\t    !folio_may_be_lru_cached(folio) || lru_cache_disabled())\nmm/mlock.c-259-\t\tmlock_folio_batch(fbatch);\n--\nmm/mlock.c=267=void mlock_new_folio(struct folio *folio)\n--\nmm/mlock.c-280-\tif (!folio_batch_add(fbatch, mlock_new(folio)) ||\nmm/mlock.c:281:\t    !folio_may_be_lru_cached(folio) || lru_cache_disabled())\nmm/mlock.c-282-\t\tmlock_folio_batch(fbatch);\n--\nmm/mlock.c=290=void munlock_folio(struct folio *folio)\n--\nmm/mlock.c-301-\tif (!folio_batch_add(fbatch, folio) ||\nmm/mlock.c:302:\t    !folio_may_be_lru_cached(folio) || lru_cache_disabled())\nmm/mlock.c-303-\t\tmlock_folio_batch(fbatch);\n--\nmm/swap.c=217=static void __folio_batch_add_and_move(struct folio_batch __percpu *fbatch,\n--\nmm/swap.c-229-\tif (!folio_batch_add(this_cpu_ptr(fbatch), folio) ||\nmm/swap.c:230:\t\t\t!folio_may_be_lru_cached(folio) || lru_cache_disabled())\nmm/swap.c-231-\t\tfolio_batch_move_lru(this_cpu_ptr(fbatch), move_fn);\n"
}

gemini-3.1-pro-preview

							input: 12797
							output: 24
							thoughts: 189

**Fuzzing Target Identification**

Okay, let's see, I've got a good starting point for fuzzing these folio functions. The `folio_may_be_lru_cached` check is a common point of interest, and these functions seem to interact with it: `collect_longterm_unpinnable_folios` in `mm/gup.c`, and the mlock functions: `mlock_folio`, `mlock_new_folio`, and `munlock_folio` from `mm/mlock.c`. I'll also bring in `__folio_batch_add_and_move` from `mm/swap.c`. These all seem like solid candidates to add to FocusSymbols.

Wait a second, though... I remember that `__folio_batch_add_and_move` is declared static. That raises a flag. We need to check its callers. Static functions can be more limiting for fuzzing if their entry points are not readily available. Let's see how it's being used. I need to be sure it's worthwhile to include it and what context the fuzzing would exercise.

{
  "Expression": "__folio_batch_add_and_move"
}

{
  "Output": "mm/swap.c=158=static void folio_batch_move_lru(struct folio_batch *fbatch, move_fn_t move_fn)\n--\nmm/swap.c-216-\nmm/swap.c:217:static void __folio_batch_add_and_move(struct folio_batch __percpu *fbatch,\nmm/swap.c-218-\t\tstruct folio *folio, move_fn_t move_fn, bool disable_irq)\n--\nmm/swap.c-239-#define folio_batch_add_and_move(folio, op)\t\t\\\nmm/swap.c:240:\t__folio_batch_add_and_move(\t\t\t\\\nmm/swap.c-241-\t\t\u0026cpu_fbatches.op,\t\t\t\\\n"
}

gemini-3.1-pro-preview

							input: 13463
							output: 23
							thoughts: 25

Here's a summary of my thought process, as requested:

**Tracing Macro Usage**

Okay, so `folio_batch_add_and_move`. That's a macro. I'm going to want to understand its impact and behavior, and to do that effectively, I need to know where it's being *used*. Time to start tracking down its invocations. Let's see where this macro is actually called. Gotta understand the contexts!

{
  "Expression": "folio_batch_add_and_move"
}

{
  "Output": "mm/swap.c=158=static void folio_batch_move_lru(struct folio_batch *fbatch, move_fn_t move_fn)\n--\nmm/swap.c-216-\nmm/swap.c:217:static void __folio_batch_add_and_move(struct folio_batch __percpu *fbatch,\nmm/swap.c-218-\t\tstruct folio *folio, move_fn_t move_fn, bool disable_irq)\n--\nmm/swap.c-238-\nmm/swap.c:239:#define folio_batch_add_and_move(folio, op)\t\t\\\nmm/swap.c:240:\t__folio_batch_add_and_move(\t\t\t\\\nmm/swap.c-241-\t\t\u0026cpu_fbatches.op,\t\t\t\\\n--\nmm/swap.c=266=void folio_rotate_reclaimable(struct folio *folio)\n--\nmm/swap.c-271-\nmm/swap.c:272:\tfolio_batch_add_and_move(folio, lru_move_tail);\nmm/swap.c-273-}\n--\nmm/swap.c=368=void folio_activate(struct folio *folio)\n--\nmm/swap.c-373-\nmm/swap.c:374:\tfolio_batch_add_and_move(folio, lru_activate);\nmm/swap.c-375-}\n--\nmm/swap.c=541=void folio_add_lru(struct folio *folio)\n--\nmm/swap.c-561-\nmm/swap.c:562:\tfolio_batch_add_and_move(folio, lru_add);\nmm/swap.c-563-}\n--\nmm/swap.c=737=void deactivate_file_folio(struct folio *folio)\n--\nmm/swap.c-745-\nmm/swap.c:746:\tfolio_batch_add_and_move(folio, lru_deactivate_file);\nmm/swap.c-747-}\n--\nmm/swap.c=757=void folio_deactivate(struct folio *folio)\n--\nmm/swap.c-764-\nmm/swap.c:765:\tfolio_batch_add_and_move(folio, lru_deactivate);\nmm/swap.c-766-}\n--\nmm/swap.c=775=void folio_mark_lazyfree(struct folio *folio)\n--\nmm/swap.c-781-\nmm/swap.c:782:\tfolio_batch_add_and_move(folio, lru_lazyfree);\nmm/swap.c-783-}\n"
}

gemini-3.1-pro-preview

							input: 14303
							output: 232
							thoughts: 429

**My Analysis of Focus Symbols and Reasoning for Fuzzing**

Alright, let's break this down. My primary concern here is the memory management subsystem, specifically around folio caching and large anonymous folio reuse. I'm going to add a list of functions to FocusSymbols: `folio_rotate_reclaimable`, `folio_activate`, `folio_add_lru`, `deactivate_file_folio`, `folio_deactivate`, and `folio_mark_lazyfree`, instead of the one function, `__folio_batch_add_and_move`.

Now, about `__wp_can_reuse_large_anon_folio`. It's static, which initially gave me pause. I know syzkaller can handle static functions within the kernel image, but providing the caller is always preferred, especially with inline functions. However, this one is not inline, so we are good.

So, let's summarize the functions I've identified as critical for focused fuzzing:

* `__wp_can_reuse_large_anon_folio`
* `collect_longterm_unpinnable_folios`
* `mlock_folio`
* `mlock_new_folio`
* `munlock_folio`
* `folio_rotate_reclaimable`
* `folio_activate`
* `folio_add_lru`
* `deactivate_file_folio`
* `folio_deactivate`
* `folio_mark_lazyfree`

These functions encompass the areas where `folio_may_be_lru_cached` is used and also the changes to `__wp_can_reuse_large_anon_folio`. The changes touch on core memory management functions and write fault handling which is a critical area for regression testing and stability.

I will also note that `TRANSPARENT_HUGEPAGE` is the relevant config.

Ultimately, these are functional changes affecting core memory management and page fault handling. Therefore, fuzzing these functions is essential to ensure we don't introduce regressions or subtle bugs. I should call `set-results`.

{
  "EnableConfigs": [
    "TRANSPARENT_HUGEPAGE"
  ],
  "FocusSymbols": [
    "__wp_can_reuse_large_anon_folio",
    "collect_longterm_unpinnable_folios",
    "mlock_folio",
    "mlock_new_folio",
    "munlock_folio",
    "folio_rotate_reclaimable",
    "folio_activate",
    "folio_add_lru",
    "deactivate_file_folio",
    "folio_deactivate",
    "folio_mark_lazyfree"
  ],
  "Reasoning": "The patch modifies the memory management subsystem, specifically the condition for caching folios in the per-CPU LRU cache (`folio_may_be_lru_cached`) and the logic for reusing large anonymous folios during write faults (`__wp_can_reuse_large_anon_folio`). These are functional changes that affect core memory management and page fault handling, which should be fuzzed to ensure no regressions or bugs are introduced.",
  "WorthFuzzing": true
}

{
  "EnableConfigs": [
    "TRANSPARENT_HUGEPAGE"
  ],
  "FocusSymbols": [
    "__wp_can_reuse_large_anon_folio",
    "collect_longterm_unpinnable_folios",
    "mlock_folio",
    "mlock_new_folio",
    "munlock_folio",
    "folio_rotate_reclaimable",
    "folio_activate",
    "folio_add_lru",
    "deactivate_file_folio",
    "folio_deactivate",
    "folio_mark_lazyfree"
  ],
  "Reasoning": "The patch modifies the memory management subsystem, specifically the condition for caching folios in the per-CPU LRU cache (`folio_may_be_lru_cached`) and the logic for reusing large anonymous folios during write faults (`__wp_can_reuse_large_anon_folio`). These are functional changes that affect core memory management and page fault handling, which should be fuzzed to ensure no regressions or bugs are introduced.",
  "WorthFuzzing": true
}

LLM Calls Summary:
Total Calls	Total Tokens	Avg Tokens	Total Duration (Seconds)	Avg Duration (Seconds)

Tool Calls Summary:
Total Calls	Total Duration (Seconds)	Avg Duration (Seconds)