syzbot


KCSAN: data-race in dont_mount / step_into_slowpath

Status: moderation: reported on 2025/12/02 12:53
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+902444170f81688c72dd@syzkaller.appspotmail.com
First crash: 100d, last: 1d06h
✨ AI Jobs (3)
ID Workflow Result Correct Bug Created Started Finished Revision Error
3784c218-3ac1-417a-aa2e-514896a1a9d6 repro KCSAN: data-race in dont_mount / step_into_slowpath 2026/03/08 05:03 2026/03/08 05:03 2026/03/08 05:10 31e9c887f7dc24e04b3ca70d0d54fc34141844b0
c60f437b-2a0f-4b4d-9643-a1b9209c8e22 assessment-kcsan Benign: ✅  Confident: ✅  KCSAN: data-race in dont_mount / step_into_slowpath 2026/02/24 22:23 2026/02/24 22:23 2026/02/24 22:34 305c0ec5cd886e2d13738e28e1b2df9b0ec20fc9
dc5f653d-5c24-4673-ad6c-db761c1c0e67 assessment-kcsan 💥 KCSAN: data-race in dont_mount / step_into_slowpath 2026/01/10 05:27 2026/01/10 05:27 2026/01/10 05:45 7519916073b761ced56a7b15fdeeb4674e8dc125 Error 429, Message: You exceeded your current quota, please check your plan and billing details. For more information on this error, head to: https://ai.google.dev/gemini-api/docs/rate-limits. To monitor your current usage, head to: https://ai.dev/rate-limit. * Quota exceeded for metric: generativelanguage.googleapis.com/generate_requests_per_model_per_day, limit: 0, Status: RESOURCE_EXHAUSTED, Details: [map[@type:type.googleapis.com/google.rpc.Help links:[map[description:Learn more about Gemini API quotas url:https://ai.google.dev/gemini-api/docs/rate-limits]]] map[@type:type.googleapis.com/google.rpc.QuotaFailure violations:[map[quotaId:GenerateRequestsPerDayPerProjectPerModel quotaMetric:generativelanguage.googleapis.com/generate_requests_per_model_per_day]]] map[@type:type.googleapis.com/google.rpc.DebugInfo detail:[ORIGINAL ERROR] generic::resource_exhausted: You exceeded your current quota, please check your plan and billing details. For more information on this error, head to: https://ai.google.dev/gemini-api/docs/rate-limits. To monitor your current usage, head to: https://ai.dev/rate-limit. * Quota exceeded for metric: generativelanguage.googleapis.com/generate_requests_per_model_per_day, limit: 0 [google.rpc.error_details_ext] { message: "You exceeded your current quota, please check your plan and billing details. For more information on this error, head to: https://ai.google.dev/gemini-api/docs/rate-limits. To monitor your current usage, head to: https://ai.dev/rate-limit. \n* Quota exceeded for metric: generativelanguage.googleapis.com/generate_requests_per_model_per_day, limit: 0" details { type_url: "type.googleapis.com/language_labs.genai.debug.GeminiApiDebugInfo" value: "RM\nK\nEgenerativelanguage.googleapis.com/generate_requests_per_model_per_day\030\000\"\000" } details { [type.googleapis.com/google.rpc.Help] { links { description: "Learn more about Gemini API quotas" url: "https://ai.google.dev/gemini-api/docs/rate-limits" } } } details { [type.googleapis.com/google.rpc.QuotaFailure] { violations { quota_metric: "generativelanguage.googleapis.com/generate_requests_per_model_per_day" quota_id: "GenerateRequestsPerDayPerProjectPerModel" } } } }]]

Sample crash report:
==================================================================
BUG: KCSAN: data-race in dont_mount / step_into_slowpath

read-write to 0xffff8881081e4a80 of 4 bytes by task 6335 on cpu 1:
 dont_mount+0x2a/0x40 include/linux/dcache.h:382
 vfs_unlink+0x206/0x490 fs/namei.c:5472
 filename_unlinkat+0x1e2/0x410 fs/namei.c:5540
 __do_sys_unlink fs/namei.c:5575 [inline]
 __se_sys_unlink+0x2b/0xe0 fs/namei.c:5572
 __x64_sys_unlink+0x1f/0x30 fs/namei.c:5572
 x64_sys_call+0x2eb6/0x3020 arch/x86/include/generated/asm/syscalls_64.h:88
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881081e4a80 of 4 bytes by task 3001 on cpu 0:
 d_managed include/linux/dcache.h:403 [inline]
 handle_mounts fs/namei.c:1733 [inline]
 step_into_slowpath+0xea/0x4c0 fs/namei.c:2101
 step_into fs/namei.c:2149 [inline]
 walk_component fs/namei.c:2285 [inline]
 lookup_last fs/namei.c:2780 [inline]
 path_lookupat+0x330/0x500 fs/namei.c:2804
 filename_lookup+0x190/0x390 fs/namei.c:2833
 do_readlinkat+0x74/0x2f0 fs/stat.c:571
 __do_sys_readlink fs/stat.c:605 [inline]
 __se_sys_readlink fs/stat.c:602 [inline]
 __x64_sys_readlink+0x47/0x60 fs/stat.c:602
 x64_sys_call+0x2b51/0x3020 arch/x86/include/generated/asm/syscalls_64.h:90
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00300080 -> 0x00004080

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3001 Comm: udevd Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
==================================================================

Crashes (31):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/11 13:27 upstream b4f0dd314b39 86914af9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/03/09 18:46 upstream 1f318b96cc84 176bead5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/03/08 21:36 upstream 014441d1e4b2 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/03/03 09:20 upstream af4e9ef3d784 28b83e23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/02/28 00:06 upstream a75cb869a8cc 2cf092b8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/02/25 07:38 upstream 7dff99b35460 787dfb7c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/02/23 05:58 upstream 6de23f81a5e0 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/02/18 20:28 upstream 23b0f90ba871 77d4d919 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/02/12 14:04 upstream c22e26bd0906 76a109e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/02/11 03:56 upstream dc855b77719f 441e25b7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/02/08 20:55 upstream e98f34af6116 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/02/05 03:59 upstream f14faaf3a1fb ea10c935 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/02/04 11:34 upstream de0674d9bc69 42b01fab .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/02/03 18:06 upstream 6bd9ed02871f 6df4c87a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/02/01 16:48 upstream ad9a728a3388 6b8752f2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/01/30 01:16 upstream 4d310797262f bfa73b7b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/01/29 22:54 upstream 8dfce8991b95 aeb6fdd5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/01/28 18:16 upstream 8dfce8991b95 004c195c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/01/26 23:33 upstream fcb70a56f4d8 efb3e894 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/01/26 07:38 upstream 023777797472 55756628 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/01/24 13:49 upstream 62085877ae65 40acda8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/01/18 22:33 upstream e84d960149e7 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/01/18 07:13 upstream d12453c7e281 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2026/01/17 15:15 upstream d3eeb99bbc99 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2025/12/25 01:26 upstream ccd1cdca5cd4 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2025/12/18 14:00 upstream ea1013c15392 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2025/12/16 18:01 upstream 40fbbd64bba6 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2025/12/13 09:02 upstream 9551a26f17d9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2025/12/04 17:34 upstream 559e608c4655 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2025/12/03 01:30 upstream d61f1cc5db79 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
2025/12/02 12:52 upstream 4a26e7032d7d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in dont_mount / step_into_slowpath
* Struck through repros no longer work on HEAD.