| Seq | Timestamp | Type | Name | Duration |
|---|---|---|---|---|
| 0/0 | 2026/09/11 08:05 | flow | patch-triage |
1mArgs:null Results: {
"EnableConfigs": null,
"FocusSymbols": [],
"KMSANReasoning": "",
"NeedsKMSAN": false,
"Reasoning": "The patch solely introduces two tracepoints (mm_mglru_scan_folios and mm_mglru_inc_max_seq) in the multi-generational LRU (MGLRU) vmscan code and extracts a small helper function (lru_gen_seq_nr_pages) to calculate generation page counts. It does not modify kernel control flow, algorithms, assertions, or data structures, making it not worth fuzzing.",
"WorthFuzzing": false
} |
| 1/1 | 2026/09/11 08:05 | action | read-patch-diff |
0mArgs:null Results: {
"PatchDiff": "commit 33831b63b7783a51535d988fc7d36e341b4e2933\nAuthor: syz-cluster \u003ctriage@syzkaller.com\u003e\nDate: Fri Sep 11 08:05:28 2026 +0000\n\n syz-cluster: applied patch under review\n\ndiff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h\nindex 8a872990b4bee..9cf3f4564afbf 100644\n--- a/include/trace/events/vmscan.h\n+++ b/include/trace/events/vmscan.h\n@@ -392,6 +392,107 @@ TRACE_EVENT(mm_vmscan_lru_isolate,\n \t\t__print_symbolic(__entry-\u003elru, LRU_NAMES))\n );\n \n+TRACE_EVENT(mm_mglru_scan_folios,\n+\n+\tTP_PROTO(u64 memcg_id,\n+\t\tint highest_zoneidx,\n+\t\tint order,\n+\t\tunsigned long nr_requested,\n+\t\tunsigned long nr_scanned,\n+\t\tunsigned long nr_sorted,\n+\t\tunsigned long nr_skipped,\n+\t\tunsigned long nr_taken,\n+\t\tint lru,\n+\t\tunsigned long max_seq,\n+\t\tint tier,\n+\t\tunsigned long min_seq),\n+\n+\tTP_ARGS(memcg_id, highest_zoneidx, order, nr_requested, nr_scanned,\n+\t\tnr_sorted, nr_skipped, nr_taken, lru, max_seq, tier, min_seq),\n+\n+\tTP_STRUCT__entry(\n+\t\t__field(u64, memcg_id)\n+\t\t__field(int, highest_zoneidx)\n+\t\t__field(int, order)\n+\t\t__field(unsigned long, nr_requested)\n+\t\t__field(unsigned long, nr_scanned)\n+\t\t__field(unsigned long, nr_sorted)\n+\t\t__field(unsigned long, nr_skipped)\n+\t\t__field(unsigned long, nr_taken)\n+\t\t__field(int, lru)\n+\t\t__field(unsigned long, max_seq)\n+\t\t__field(int, tier)\n+\t\t__field(unsigned long, min_seq)\n+\t),\n+\n+\tTP_fast_assign(\n+\t\t__entry-\u003ememcg_id = memcg_id;\n+\t\t__entry-\u003ehighest_zoneidx = highest_zoneidx;\n+\t\t__entry-\u003eorder = order;\n+\t\t__entry-\u003enr_requested = nr_requested;\n+\t\t__entry-\u003enr_scanned = nr_scanned;\n+\t\t__entry-\u003enr_sorted = nr_sorted;\n+\t\t__entry-\u003enr_skipped = nr_skipped;\n+\t\t__entry-\u003enr_taken = nr_taken;\n+\t\t__entry-\u003elru = lru;\n+\t\t__entry-\u003emax_seq = max_seq;\n+\t\t__entry-\u003etier = tier;\n+\t\t__entry-\u003emin_seq = min_seq;\n+\t),\n+\n+\tTP_printk(\"memcg_id=%llu classzone=%d order=%d nr_requested=%lu nr_scanned=%lu nr_sorted=%lu nr_skipped=%lu nr_taken=%lu lru=%s max_seq=%lu tier=%d min_seq=%lu\",\n+\t\t__entry-\u003ememcg_id,\n+\t\t__entry-\u003ehighest_zoneidx,\n+\t\t__entry-\u003eorder,\n+\t\t__entry-\u003enr_requested,\n+\t\t__entry-\u003enr_scanned,\n+\t\t__entry-\u003enr_sorted,\n+\t\t__entry-\u003enr_skipped,\n+\t\t__entry-\u003enr_taken,\n+\t\t__print_symbolic(__entry-\u003elru, LRU_NAMES),\n+\t\t__entry-\u003emax_seq,\n+\t\t__entry-\u003etier,\n+\t\t__entry-\u003emin_seq)\n+);\n+\n+TRACE_EVENT(mm_mglru_inc_max_seq,\n+\n+\tTP_PROTO(u64 memcg_id,\n+\t\tunsigned long max_seq,\n+\t\tunsigned long anon_min_seq,\n+\t\tunsigned long file_min_seq,\n+\t\tunsigned long *nr_anon,\n+\t\tunsigned long *nr_file),\n+\n+\tTP_ARGS(memcg_id, max_seq, anon_min_seq, file_min_seq, nr_anon, nr_file),\n+\n+\tTP_STRUCT__entry(\n+\t\t__field(u64, memcg_id)\n+\t\t__field(unsigned long, max_seq)\n+\t\t__field(unsigned long, anon_min_seq)\n+\t\t__field(unsigned long, file_min_seq)\n+\t\t__array(unsigned long, nr_anon, MAX_NR_GENS)\n+\t\t__array(unsigned long, nr_file, MAX_NR_GENS)\n+\t),\n+\n+\tTP_fast_assign(\n+\t\t__entry-\u003ememcg_id = memcg_id;\n+\t\t__entry-\u003emax_seq = max_seq;\n+\t\t__entry-\u003eanon_min_seq = anon_min_seq;\n+\t\t__entry-\u003efile_min_seq = file_min_seq;\n+\t\tmemcpy(__entry-\u003enr_anon, nr_anon, sizeof(__entry-\u003enr_anon));\n+\t\tmemcpy(__entry-\u003enr_file, nr_file, sizeof(__entry-\u003enr_file));\n+\t),\n+\n+\tTP_printk(\"memcg_id=%llu max_seq=%lu anon_min_seq=%lu file_min_seq=%lu nr_anon=%s nr_file=%s\",\n+\t\t__entry-\u003ememcg_id,\n+\t\t__entry-\u003emax_seq,\n+\t\t__entry-\u003eanon_min_seq,\n+\t\t__entry-\u003efile_min_seq,\n+\t\t__print_array(__entry-\u003enr_anon, MAX_NR_GENS, sizeof(unsigned long)),\n+\t\t__print_array(__entry-\u003enr_file, MAX_NR_GENS, sizeof(unsigned long)))\n+);\n+\n TRACE_EVENT(mm_vmscan_write_folio,\n \n \tTP_PROTO(struct folio *folio),\ndiff --git a/mm/vmscan.c b/mm/vmscan.c\nindex 40d3f1b48a74c..d0e59baf5d5c6 100644\n--- a/mm/vmscan.c\n+++ b/mm/vmscan.c\n@@ -2813,6 +2813,18 @@ static int get_nr_gens(struct lruvec *lruvec, int type)\n \treturn lruvec-\u003elrugen.max_seq - lruvec-\u003elrugen.min_seq[type] + 1;\n }\n \n+/* the number of pages in a generation, summed over zones and clamped to \u003e= 0 */\n+static unsigned long lru_gen_seq_nr_pages(struct lru_gen_folio *lrugen, int gen, int type)\n+{\n+\tint zone;\n+\tunsigned long size = 0;\n+\n+\tfor (zone = 0; zone \u003c MAX_NR_ZONES; zone++)\n+\t\tsize += max(READ_ONCE(lrugen-\u003enr_pages[gen][type][zone]), 0L);\n+\n+\treturn size;\n+}\n+\n static bool __maybe_unused seq_is_valid(struct lruvec *lruvec)\n {\n \tint type;\n@@ -4088,6 +4100,26 @@ static void try_to_inc_min_seq(struct lruvec *lruvec, int swappiness)\n \t}\n }\n \n+static void trace_inc_max_seq(struct lruvec *lruvec)\n+{\n+\tint type, gen;\n+\tunsigned long nr[ANON_AND_FILE][MAX_NR_GENS];\n+\tstruct lru_gen_folio *lrugen = \u0026lruvec-\u003elrugen;\n+\n+\tif (!trace_mm_mglru_inc_max_seq_enabled())\n+\t\treturn;\n+\n+\tfor (type = 0; type \u003c ANON_AND_FILE; type++)\n+\t\tfor (gen = 0; gen \u003c MAX_NR_GENS; gen++)\n+\t\t\tnr[type][gen] = lru_gen_seq_nr_pages(lrugen, gen, type);\n+\n+\ttrace_mm_mglru_inc_max_seq(mem_cgroup_id(lruvec_memcg(lruvec)),\n+\t\t\t\t lrugen-\u003emax_seq,\n+\t\t\t\t lrugen-\u003emin_seq[LRU_GEN_ANON],\n+\t\t\t\t lrugen-\u003emin_seq[LRU_GEN_FILE],\n+\t\t\t\t nr[LRU_GEN_ANON], nr[LRU_GEN_FILE]);\n+}\n+\n static bool inc_max_seq(struct lruvec *lruvec, unsigned long seq, int swappiness)\n {\n \tbool success;\n@@ -4147,6 +4179,8 @@ static bool inc_max_seq(struct lruvec *lruvec, unsigned long seq, int swappiness\n \tWRITE_ONCE(lrugen-\u003etimestamps[next], jiffies);\n \t/* make sure preceding modifications appear */\n \tsmp_store_release(\u0026lrugen-\u003emax_seq, lrugen-\u003emax_seq + 1);\n+\n+\ttrace_inc_max_seq(lruvec);\n unlock:\n \tlruvec_unlock_irq(lruvec);\n \n@@ -4239,7 +4273,7 @@ static void set_initial_priority(struct pglist_data *pgdat, struct scan_control\n \n static unsigned long lruvec_evictable_size(struct lruvec *lruvec, int swappiness)\n {\n-\tint gen, type, zone;\n+\tint gen, type;\n \tunsigned long seq, total = 0;\n \tstruct lru_gen_folio *lrugen = \u0026lruvec-\u003elrugen;\n \tDEFINE_MAX_SEQ(lruvec);\n@@ -4248,8 +4282,7 @@ static unsigned long lruvec_evictable_size(struct lruvec *lruvec, int swappiness\n \tfor_each_evictable_type(type, swappiness) {\n \t\tfor (seq = min_seq[type]; seq \u003c= max_seq; seq++) {\n \t\t\tgen = lru_gen_from_seq(seq);\n-\t\t\tfor (zone = 0; zone \u003c MAX_NR_ZONES; zone++)\n-\t\t\t\ttotal += max(READ_ONCE(lrugen-\u003enr_pages[gen][type][zone]), 0L);\n+\t\t\ttotal += lru_gen_seq_nr_pages(lrugen, gen, type);\n \t\t}\n \t}\n \n@@ -4865,6 +4898,12 @@ static int scan_folios(unsigned long nr_to_scan, struct lruvec *lruvec,\n \ttrace_mm_vmscan_lru_isolate(sc-\u003ereclaim_idx, sc-\u003eorder, nr_to_scan,\n \t\t\t\tscanned, skipped, isolated,\n \t\t\t\ttype ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON);\n+\ttrace_mm_mglru_scan_folios(mem_cgroup_id(lruvec_memcg(lruvec)),\n+\t\t\t\t sc-\u003ereclaim_idx, sc-\u003eorder, nr_to_scan,\n+\t\t\t\t scanned, sorted, skipped, isolated,\n+\t\t\t\t type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON,\n+\t\t\t\t lrugen-\u003emax_seq, tier,\n+\t\t\t\t lrugen-\u003emin_seq[type]);\n \n \t*isolatedp = isolated;\n \treturn scanned;\n@@ -5738,19 +5777,16 @@ static int lru_gen_seq_show(struct seq_file *m, void *v)\n \t\tseq = 0;\n \n \tfor (; seq \u003c= max_seq; seq++) {\n-\t\tint type, zone;\n+\t\tint type;\n \t\tint gen = lru_gen_from_seq(seq);\n \t\tunsigned long birth = READ_ONCE(lruvec-\u003elrugen.timestamps[gen]);\n \n \t\tseq_printf(m, \" %10lu %10u\", seq, jiffies_to_msecs(jiffies - birth));\n \n \t\tfor (type = 0; type \u003c ANON_AND_FILE; type++) {\n-\t\t\tunsigned long size = 0;\n+\t\t\tunsigned long size = lru_gen_seq_nr_pages(lrugen, gen, type);\n \t\t\tchar mark = full \u0026\u0026 seq \u003c min_seq[type] ? 'x' : ' ';\n \n-\t\t\tfor (zone = 0; zone \u003c MAX_NR_ZONES; zone++)\n-\t\t\t\tsize += max(READ_ONCE(lrugen-\u003enr_pages[gen][type][zone]), 0L);\n-\n \t\t\tseq_printf(m, \" %10lu%c\", size, mark);\n \t\t}\n \n"
} |
| 2/1 | 2026/09/11 08:05 | agent | patch-evaluator |
1mModel:core Args: null Results: {
"EnableConfigs": null,
"FocusSymbols": [],
"Reasoning": "The patch solely introduces two tracepoints (mm_mglru_scan_folios and mm_mglru_inc_max_seq) in the multi-generational LRU (MGLRU) vmscan code and extracts a small helper function (lru_gen_seq_nr_pages) to calculate generation page counts. It does not modify kernel control flow, algorithms, assertions, or data structures, making it not worth fuzzing.",
"WorthFuzzing": false
}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 33831b63b7783a51535d988fc7d36e341b4e2933
Author: syz-cluster <triage@syzkaller.com>
Date: Fri Sep 11 08:05:28 2026 +0000
syz-cluster: applied patch under review
diff --git a/include/trace/events/vmscan.h b/include/trace/events/vmscan.h
index 8a872990b4bee..9cf3f4564afbf 100644
--- a/include/trace/events/vmscan.h
+++ b/include/trace/events/vmscan.h
@@ -392,6 +392,107 @@ TRACE_EVENT(mm_vmscan_lru_isolate,
__print_symbolic(__entry->lru, LRU_NAMES))
);
+TRACE_EVENT(mm_mglru_scan_folios,
+
+ TP_PROTO(u64 memcg_id,
+ int highest_zoneidx,
+ int order,
+ unsigned long nr_requested,
+ unsigned long nr_scanned,
+ unsigned long nr_sorted,
+ unsigned long nr_skipped,
+ unsigned long nr_taken,
+ int lru,
+ unsigned long max_seq,
+ int tier,
+ unsigned long min_seq),
+
+ TP_ARGS(memcg_id, highest_zoneidx, order, nr_requested, nr_scanned,
+ nr_sorted, nr_skipped, nr_taken, lru, max_seq, tier, min_seq),
+
+ TP_STRUCT__entry(
+ __field(u64, memcg_id)
+ __field(int, highest_zoneidx)
+ __field(int, order)
+ __field(unsigned long, nr_requested)
+ __field(unsigned long, nr_scanned)
+ __field(unsigned long, nr_sorted)
+ __field(unsigned long, nr_skipped)
+ __field(unsigned long, nr_taken)
+ __field(int, lru)
+ __field(unsigned long, max_seq)
+ __field(int, tier)
+ __field(unsigned long, min_seq)
+ ),
+
+ TP_fast_assign(
+ __entry->memcg_id = memcg_id;
+ __entry->highest_zoneidx = highest_zoneidx;
+ __entry->order = order;
+ __entry->nr_requested = nr_requested;
+ __entry->nr_scanned = nr_scanned;
+ __entry->nr_sorted = nr_sorted;
+ __entry->nr_skipped = nr_skipped;
+ __entry->nr_taken = nr_taken;
+ __entry->lru = lru;
+ __entry->max_seq = max_seq;
+ __entry->tier = tier;
+ __entry->min_seq = min_seq;
+ ),
+
+ TP_printk("memcg_id=%llu classzone=%d order=%d nr_requested=%lu nr_scanned=%lu nr_sorted=%lu nr_skipped=%lu nr_taken=%lu lru=%s max_seq=%lu tier=%d min_seq=%lu",
+ __entry->memcg_id,
+ __entry->highest_zoneidx,
+ __entry->order,
+ __entry->nr_requested,
+ __entry->nr_scanned,
+ __entry->nr_sorted,
+ __entry->nr_skipped,
+ __entry->nr_taken,
+ __print_symbolic(__entry->lru, LRU_NAMES),
+ __entry->max_seq,
+ __entry->tier,
+ __entry->min_seq)
+);
+
+TRACE_EVENT(mm_mglru_inc_max_seq,
+
+ TP_PROTO(u64 memcg_id,
+ unsigned long max_seq,
+ unsigned long anon_min_seq,
+ unsigned long file_min_seq,
+ unsigned long *nr_anon,
+ unsigned long *nr_file),
+
+ TP_ARGS(memcg_id, max_seq, anon_min_seq, file_min_seq, nr_anon, nr_file),
+
+ TP_STRUCT__entry(
+ __field(u64, memcg_id)
+ __field(unsigned long, max_seq)
+ __field(unsigned long, anon_min_seq)
+ __field(unsigned long, file_min_seq)
+ __array(unsigned long, nr_anon, MAX_NR_GENS)
+ __array(unsigned long, nr_file, MAX_NR_GENS)
+ ),
+
+ TP_fast_assign(
+ __entry->memcg_id = memcg_id;
+ __entry->max_seq = max_seq;
+ __entry->anon_min_seq = anon_min_seq;
+ __entry->file_min_seq = file_min_seq;
+ memcpy(__entry->nr_anon, nr_anon, sizeof(__entry->nr_anon));
+ memcpy(__entry->nr_file, nr_file, sizeof(__entry->nr_file));
+ ),
+
+ TP_printk("memcg_id=%llu max_seq=%lu anon_min_seq=%lu file_min_seq=%lu nr_anon=%s nr_file=%s",
+ __entry->memcg_id,
+ __entry->max_seq,
+ __entry->anon_min_seq,
+ __entry->file_min_seq,
+ __print_array(__entry->nr_anon, MAX_NR_GENS, sizeof(unsigned long)),
+ __print_array(__entry->nr_file, MAX_NR_GENS, sizeof(unsigned long)))
+);
+
TRACE_EVENT(mm_vmscan_write_folio,
TP_PROTO(struct folio *folio),
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 40d3f1b48a74c..d0e59baf5d5c6 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2813,6 +2813,18 @@ static int get_nr_gens(struct lruvec *lruvec, int type)
return lruvec->lrugen.max_seq - lruvec->lrugen.min_seq[type] + 1;
}
+/* the number of pages in a generation, summed over zones and clamped to >= 0 */
+static unsigned long lru_gen_seq_nr_pages(struct lru_gen_folio *lrugen, int gen, int type)
+{
+ int zone;
+ unsigned long size = 0;
+
+ for (zone = 0; zone < MAX_NR_ZONES; zone++)
+ size += max(READ_ONCE(lrugen->nr_pages[gen][type][zone]), 0L);
+
+ return size;
+}
+
static bool __maybe_unused seq_is_valid(struct lruvec *lruvec)
{
int type;
@@ -4088,6 +4100,26 @@ static void try_to_inc_min_seq(struct lruvec *lruvec, int swappiness)
}
}
+static void trace_inc_max_seq(struct lruvec *lruvec)
+{
+ int type, gen;
+ unsigned long nr[ANON_AND_FILE][MAX_NR_GENS];
+ struct lru_gen_folio *lrugen = &lruvec->lrugen;
+
+ if (!trace_mm_mglru_inc_max_seq_enabled())
+ return;
+
+ for (type = 0; type < ANON_AND_FILE; type++)
+ for (gen = 0; gen < MAX_NR_GENS; gen++)
+ nr[type][gen] = lru_gen_seq_nr_pages(lrugen, gen, type);
+
+ trace_mm_mglru_inc_max_seq(mem_cgroup_id(lruvec_memcg(lruvec)),
+ lrugen->max_seq,
+ lrugen->min_seq[LRU_GEN_ANON],
+ lrugen->min_seq[LRU_GEN_FILE],
+ nr[LRU_GEN_ANON], nr[LRU_GEN_FILE]);
+}
+
static bool inc_max_seq(struct lruvec *lruvec, unsigned long seq, int swappiness)
{
bool success;
@@ -4147,6 +4179,8 @@ static bool inc_max_seq(struct lruvec *lruvec, unsigned long seq, int swappiness
WRITE_ONCE(lrugen->timestamps[next], jiffies);
/* make sure preceding modifications appear */
smp_store_release(&lrugen->max_seq, lrugen->max_seq + 1);
+
+ trace_inc_max_seq(lruvec);
unlock:
lruvec_unlock_irq(lruvec);
@@ -4239,7 +4273,7 @@ static void set_initial_priority(struct pglist_data *pgdat, struct scan_control
static unsigned long lruvec_evictable_size(struct lruvec *lruvec, int swappiness)
{
- int gen, type, zone;
+ int gen, type;
unsigned long seq, total = 0;
struct lru_gen_folio *lrugen = &lruvec->lrugen;
DEFINE_MAX_SEQ(lruvec);
@@ -4248,8 +4282,7 @@ static unsigned long lruvec_evictable_size(struct lruvec *lruvec, int swappiness
for_each_evictable_type(type, swappiness) {
for (seq = min_seq[type]; seq <= max_seq; seq++) {
gen = lru_gen_from_seq(seq);
- for (zone = 0; zone < MAX_NR_ZONES; zone++)
- total += max(READ_ONCE(lrugen->nr_pages[gen][type][zone]), 0L);
+ total += lru_gen_seq_nr_pages(lrugen, gen, type);
}
}
@@ -4865,6 +4898,12 @@ static int scan_folios(unsigned long nr_to_scan, struct lruvec *lruvec,
trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan,
scanned, skipped, isolated,
type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON);
+ trace_mm_mglru_scan_folios(mem_cgroup_id(lruvec_memcg(lruvec)),
+ sc->reclaim_idx, sc->order, nr_to_scan,
+ scanned, sorted, skipped, isolated,
+ type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON,
+ lrugen->max_seq, tier,
+ lrugen->min_seq[type]);
*isolatedp = isolated;
return scanned;
@@ -5738,19 +5777,16 @@ static int lru_gen_seq_show(struct seq_file *m, void *v)
seq = 0;
for (; seq <= max_seq; seq++) {
- int type, zone;
+ int type;
int gen = lru_gen_from_seq(seq);
unsigned long birth = READ_ONCE(lruvec->lrugen.timestamps[gen]);
seq_printf(m, " %10lu %10u", seq, jiffies_to_msecs(jiffies - birth));
for (type = 0; type < ANON_AND_FILE; type++) {
- unsigned long size = 0;
+ unsigned long size = lru_gen_seq_nr_pages(lrugen, gen, type);
char mark = full && seq < min_seq[type] ? 'x' : ' ';
- for (zone = 0; zone < MAX_NR_ZONES; zone++)
- size += max(READ_ONCE(lrugen->nr_pages[gen][type][zone]), 0L);
-
seq_printf(m, " %10lu%c", size, mark);
}
|
| 3/2 | 2026/09/11 08:05 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 5799 output: 23 thoughts: 1401 Thoughts: **Evaluating the Patch for Syzkaller Fuzzing Potential** Okay, let's break this down. My goal is to determine if this patch series warrants inclusion in our fuzzing efforts with syzkaller. First, let's analyze the diff. We see additions: two new tracepoints, `mm_mglru_scan_folios` and `mm_mglru_inc_max_seq`, in `include/trace/events/vmscan.h`. Also, a new helper function, `lru_gen_seq_nr_pages`, and uses of these new additions in `mm/vmscan.c`. Now, the crucial question. According to our criteria, we don't want to fuzz patches that are non-kernel, non-executable changes. And more specifically: "Purely decorative logging (e.g., message strings in pr_err, printk, dev_info) or tracepoints that do not alter control flow or data structures." That is the key test here. Initially, it looks like this might fall into that category: essentially new tracepoints, a bit of refactoring, and adding a 3-line sum function. It appears to be mostly about observability. However, let's dive deeper and scrutinize the code changes. Does the new helper function, `lru_gen_seq_nr_pages`, actually impact control flow or data structures? Looking closely at `lruvec_evictable_size`, `lru_gen_seq_show`, and `trace_inc_max_seq` it's just a direct, one-to-one replacement of the for loop. The helper function sums array elements, nothing more, nothing less. It's a straight code refactoring to DRY the code. And the tracepoints themselves only add instrumentation, not alter logic. In `scan_folios`, the tracepoint simply logs information without affecting the program's path. So, am I missing anything? The code changes appear strictly cosmetic in terms of altering data or control flow. Let's make sure, before making a final decision. I should probably run `git diff` one more time or verify with other tools for a quick double check, just in case. In conclusion, given that this patch seems limited to tracepoint additions and a trivial helper function for code deduplication that doesn't modify data structures or control flow, my assessment is that this patch series is *not* worth fuzzing at this time. |
| 4/2 | 2026/09/11 08:06 | tool | grepper |
0mArgs:{
"Expression": "mm_mglru_scan_folios"
}Results: {
"Output": "include/trace/events/vmscan.h=350=TRACE_EVENT(mm_vmscan_lru_isolate,\n--\ninclude/trace/events/vmscan.h-394-\ninclude/trace/events/vmscan.h:395:TRACE_EVENT(mm_mglru_scan_folios,\ninclude/trace/events/vmscan.h-396-\n--\nmm/vmscan.c=4831=static int scan_folios(unsigned long nr_to_scan, struct lruvec *lruvec,\n--\nmm/vmscan.c-4900-\t\t\t\ttype ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON);\nmm/vmscan.c:4901:\ttrace_mm_mglru_scan_folios(mem_cgroup_id(lruvec_memcg(lruvec)),\nmm/vmscan.c-4902-\t\t\t\t sc-\u003ereclaim_idx, sc-\u003eorder, nr_to_scan,\n"
} |
| 5/2 | 2026/09/11 08:06 | llm | patch-evaluator |
0mModel:gemini-3.7-flash Args: null Results: null Tokens: input: 8000 output: 123 thoughts: 379 Thoughts: **My Assessment of the Patch's Fuzzing Worthiness** Okay, before I sign off on this, let's just double-check the git history and diff to be absolutely certain nothing else sneaked in. I'll probably fire up `read-file` or `grepper` if I need to dig deeper. That commit ID is `33831b63b7783a51535d988fc7d36e341b4e2933`. Now, let's revisit the fuzzing guidelines. Specifically, the bit about: "Purely decorative logging (e.g., message strings in pr_err, printk, dev_info) or tracepoints that do not alter control flow or data structures." That's the key here, and if that applies, then `WorthFuzzing` should be `false`. Does this patch *actually* do anything other than inject tracepoints and refactor this helper? Let's see... It looks like it's adding two tracepoints, `mm_mglru_scan_folios` and `mm_mglru_inc_max_seq`, along with this little static helper `lru_gen_seq_nr_pages`. It seems this helper is *only* used by the tracepoints, and it's basically the same logic that was already open-coded in a couple of places. No changes to control flow, data structures, or any critical invariants are happening. Right, so under Section 2 of the guidelines, that "Purely decorative logging" bit definitely applies here. The patch just adds these tracepoints, and extracts this helper function. Nothing more. So, `WorthFuzzing` is unequivocally `false`. Let's summarize and confirm. - `WorthFuzzing: false` - `FocusSymbols: []` - `EnableConfigs: []` - `Reasoning: Concise explanation.` Okay, time to call `set-results`. |
| 6/2 | 2026/09/11 08:06 | tool | set-results |
0mArgs:{
"EnableConfigs": [],
"FocusSymbols": [],
"Reasoning": "The patch solely introduces two tracepoints (mm_mglru_scan_folios and mm_mglru_inc_max_seq) in the multi-generational LRU (MGLRU) vmscan code and extracts a small helper function (lru_gen_seq_nr_pages) to calculate generation page counts. It does not modify kernel control flow, algorithms, assertions, or data structures, making it not worth fuzzing.",
"WorthFuzzing": false
}Results: {
"EnableConfigs": null,
"FocusSymbols": [],
"Reasoning": "The patch solely introduces two tracepoints (mm_mglru_scan_folios and mm_mglru_inc_max_seq) in the multi-generational LRU (MGLRU) vmscan code and extracts a small helper function (lru_gen_seq_nr_pages) to calculate generation page counts. It does not modify kernel control flow, algorithms, assertions, or data structures, making it not worth fuzzing.",
"WorthFuzzing": false
} |
| 7/1 | 2026/09/11 08:06 | action | If |
0mArgs:{
"WorthFuzzing": false
}Results: null |
| Total Calls | Total Tokens | Avg Tokens | Total Duration (Seconds) | Avg Duration (Seconds) |
|---|
| Total Calls | Total Duration (Seconds) | Avg Duration (Seconds) |
|---|