KCSAN: data-race in __set_task_comm / strlen (2)

Status: moderation: reported C repro on 2026/08/04 08:46
Subsystems: fs mm
Labels: race:benign prio:low
[Documentation on labels]
Reported-by: syzbot+98baf51f5cc36dcbe2f7@syzkaller.appspotmail.com
First crash: 93d, last: 19h26m
▶ ▼ ✨ AI Jobs (3)
ID Workflow Result Correct Bug Created Started Finished Revision
b47be812 repro-c Reproduced: ✅ ❓ KCSAN: data-race in __set_task_comm / strlen (2) 2026/10/15 12:01 2026/10/15 12:01 2026/10/15 12:18 8fb0ae89
736576bd assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KCSAN: data-race in __set_task_comm / strlen (2) 2026/08/09 11:33 2026/08/09 11:33 2026/08/09 12:12 5d63f80b
9011fcab assessment-kcsan Benign: ✅ ❓ KCSAN: data-race in __set_task_comm / strlen (2) 2026/08/04 08:45 2026/08/04 08:45 2026/08/04 09:18 9451e17e
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __set_task_comm / strlen fs mm 6 9 251d 421d 0/29 auto-obsoleted due to no activity on 2026/04/23 17:03
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2026/10/15 23:31 10m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 9aa622dbaab8addcbe6f65f17c7b4d613d270f05 report job log log

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __set_task_comm / strlen

read to 0xffff888103b3ccd8 of 1 bytes by task 3683 on cpu 1:
 strlen+0x19/0x40 lib/string.c:402
 __fortify_strlen include/linux/fortify-string.h:218 [inline]
 trace_event_get_offsets_sched_stat_runtime include/trace/events/sched.h:560 [inline]
 do_trace_event_raw_event_sched_stat_runtime include/trace/events/sched.h:553 [inline]
 trace_event_raw_event_sched_stat_runtime+0x5a/0x150 include/trace/events/sched.h:553
 __do_trace_sched_stat_runtime include/trace/events/sched.h:576 [inline]
 trace_sched_stat_runtime include/trace/events/sched.h:576 [inline]
 update_se+0x14f/0x3b0 kernel/sched/fair.c:1425
 update_curr+0x1e/0x210 kernel/sched/fair.c:2239
 update_curr_eevdf kernel/sched/fair.c:8196 [inline]
 enqueue_task_fair+0x77/0x850 kernel/sched/fair.c:8226
 enqueue_task kernel/sched/core.c:2194 [inline]
 activate_task kernel/sched/core.c:2234 [inline]
 ttwu_do_activate+0xa7/0x230 kernel/sched/core.c:3847
 ttwu_queue kernel/sched/core.c:4100 [inline]
 try_to_wake_up+0x44f/0x6d0 kernel/sched/core.c:4438
 wake_up_process kernel/sched/core.c:4570 [inline]
 wake_up_q+0x48/0x80 kernel/sched/core.c:1183
 futex_wake+0x376/0x400 kernel/futex/waitwake.c:225
 do_futex+0x3f8/0x460 kernel/futex/syscalls.c:138
 __do_sys_futex kernel/futex/syscalls.c:210 [inline]
 __se_sys_futex+0x2f6/0x370 kernel/futex/syscalls.c:191
 __x64_sys_futex+0x78/0x90 kernel/futex/syscalls.c:191
 x64_sys_call+0x22e2/0x2550 arch/x86/include/generated/asm/syscalls_64.h:203
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff888103b3ccd8 of 10 bytes by task 3682 on cpu 0:
 __set_task_comm+0x78/0x180 fs/exec.c:1103
 __do_sys_prctl kernel/sys.c:2608 [inline]
 __se_sys_prctl+0xcb3/0x13b0 kernel/sys.c:2534
 __x64_sys_prctl+0x67/0x80 kernel/sys.c:2534
 x64_sys_call+0x2421/0x2550 arch/x86/include/generated/asm/syscalls_64.h:158
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3682 Comm: BBBBBBBBBB Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
==================================================================
==================================================================
BUG: KCSAN: data-race in __set_task_comm / strlen

read to 0xffff888103b3ccd8 of 1 bytes by task 3683 on cpu 1:
 strlen+0x19/0x40 lib/string.c:402
 __fortify_strlen include/linux/fortify-string.h:218 [inline]
 trace_event_get_offsets_sched_stat_runtime include/trace/events/sched.h:560 [inline]
 do_trace_event_raw_event_sched_stat_runtime include/trace/events/sched.h:553 [inline]
 trace_event_raw_event_sched_stat_runtime+0x5a/0x150 include/trace/events/sched.h:553
 __do_trace_sched_stat_runtime include/trace/events/sched.h:576 [inline]
 trace_sched_stat_runtime include/trace/events/sched.h:576 [inline]
 update_se+0x14f/0x3b0 kernel/sched/fair.c:1425
 update_curr+0x1e/0x210 kernel/sched/fair.c:2239
 update_curr_eevdf kernel/sched/fair.c:8196 [inline]
 enqueue_task_fair+0x77/0x850 kernel/sched/fair.c:8226
 enqueue_task kernel/sched/core.c:2194 [inline]
 activate_task kernel/sched/core.c:2234 [inline]
 ttwu_do_activate+0xa7/0x230 kernel/sched/core.c:3847
 ttwu_queue kernel/sched/core.c:4100 [inline]
 try_to_wake_up+0x44f/0x6d0 kernel/sched/core.c:4438
 wake_up_process kernel/sched/core.c:4570 [inline]
 wake_up_q+0x48/0x80 kernel/sched/core.c:1183
 futex_wake+0x376/0x400 kernel/futex/waitwake.c:225
 do_futex+0x3f8/0x460 kernel/futex/syscalls.c:138
 __do_sys_futex kernel/futex/syscalls.c:210 [inline]
 __se_sys_futex+0x2f6/0x370 kernel/futex/syscalls.c:191
 __x64_sys_futex+0x78/0x90 kernel/futex/syscalls.c:191
 x64_sys_call+0x22e2/0x2550 arch/x86/include/generated/asm/syscalls_64.h:203
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff888103b3ccd8 of 10 bytes by task 3682 on cpu 0:
 __set_task_comm+0x78/0x180 fs/exec.c:1103
 __do_sys_prctl kernel/sys.c:2608 [inline]
 __se_sys_prctl+0xcb3/0x13b0 kernel/sys.c:2534
 __x64_sys_prctl+0x67/0x80 kernel/sys.c:2534
 x64_sys_call+0x2421/0x2550 arch/x86/include/generated/asm/syscalls_64.h:158
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3682 Comm: BBBBBBBBBB Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
==================================================================
==================================================================
BUG: KCSAN: data-race in __set_task_comm / strlen

read to 0xffff888103b3ccd8 of 1 bytes by task 3683 on cpu 1:
 strlen+0x19/0x40 lib/string.c:402
 __fortify_strlen include/linux/fortify-string.h:218 [inline]
 trace_event_get_offsets_sched_stat_runtime include/trace/events/sched.h:560 [inline]
 do_trace_event_raw_event_sched_stat_runtime include/trace/events/sched.h:553 [inline]
 trace_event_raw_event_sched_stat_runtime+0x5a/0x150 include/trace/events/sched.h:553
 __do_trace_sched_stat_runtime include/trace/events/sched.h:576 [inline]
 trace_sched_stat_runtime include/trace/events/sched.h:576 [inline]
 update_se+0x14f/0x3b0 kernel/sched/fair.c:1425
 update_curr+0x1e/0x210 kernel/sched/fair.c:2239
 update_curr_eevdf kernel/sched/fair.c:8196 [inline]
 enqueue_task_fair+0x77/0x850 kernel/sched/fair.c:8226
 enqueue_task kernel/sched/core.c:2194 [inline]
 activate_task kernel/sched/core.c:2234 [inline]
 ttwu_do_activate+0xa7/0x230 kernel/sched/core.c:3847
 ttwu_queue kernel/sched/core.c:4100 [inline]
 try_to_wake_up+0x44f/0x6d0 kernel/sched/core.c:4438
 wake_up_process kernel/sched/core.c:4570 [inline]
 wake_up_q+0x48/0x80 kernel/sched/core.c:1183
 futex_wake+0x376/0x400 kernel/futex/waitwake.c:225
 do_futex+0x3f8/0x460 kernel/futex/syscalls.c:138
 __do_sys_futex kernel/futex/syscalls.c:210 [inline]
 __se_sys_futex+0x2f6/0x370 kernel/futex/syscalls.c:191
 __x64_sys_futex+0x78/0x90 kernel/futex/syscalls.c:191
 x64_sys_call+0x22e2/0x2550 arch/x86/include/generated/asm/syscalls_64.h:203
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff888103b3ccd8 of 10 bytes by task 3682 on cpu 0:
 __set_task_comm+0x78/0x180 fs/exec.c:1103
 __do_sys_prctl kernel/sys.c:2608 [inline]
 __se_sys_prctl+0xcb3/0x13b0 kernel/sys.c:2534
 __x64_sys_prctl+0x67/0x80 kernel/sys.c:2534
 x64_sys_call+0x2421/0x2550 arch/x86/include/generated/asm/syscalls_64.h:158
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3682 Comm: BBBBBBBBBB Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
==================================================================

Crashes (134):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/15 23:42 git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 9aa622dbaab8 8fb0ae89 .config console log report C ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/11/04 19:24 upstream 05441d697f7f 73438ed0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/11/03 23:26 upstream 05441d697f7f e2d35131 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/11/02 12:46 upstream 6628e7d4c6b2 6969b601 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/11/01 16:19 upstream cbbddb6b08cc 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/31 20:46 upstream 36aad21d50d1 2041d3f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/31 06:15 upstream bd5c762ac051 0ec395f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/26 14:13 upstream 6b4b543fa187 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/25 23:33 upstream 21a7f44fd076 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/24 18:36 upstream 5b0764a53235 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/23 19:47 upstream 734bef548a96 1d9ca40b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/23 05:29 upstream a1c2b1da93f5 d566bfda .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/21 05:49 upstream 4cbdd58dfa7a 61c200c7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/21 02:35 upstream 4cbdd58dfa7a df8746fb .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/20 14:49 upstream f47d223627f8 df8746fb .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/20 00:38 upstream c03c1a14507d 72cdc28d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/19 01:07 upstream a0ff06b3a7bd 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/18 14:28 upstream 32c52ec87d62 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/17 17:02 upstream 58161ead29e5 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/17 03:49 upstream 70dd4ee72eb2 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/16 13:23 upstream 2f2f7eeef8b0 4c840a2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/15 06:37 upstream 0fcb05b72344 8fb0ae89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/14 16:55 upstream 4056b3c9d3c9 1a71827b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/14 02:28 upstream ca3e345926b0 7321cd29 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/12 14:59 upstream 24a19b953e2a 745a967f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/12 11:45 upstream 24a19b953e2a 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/11 16:57 upstream b88c841d1164 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/11 10:31 upstream a5ebb76233b7 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/10 21:13 upstream 3857c2fe5449 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/10 00:07 upstream fc1c25014ff8 4f92358f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/09 10:52 upstream af32da41b032 b2734a59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/09 00:23 upstream 6c377d19d4a5 b2734a59 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/08 09:52 upstream 7b63ef2d55f2 4f6a9fcf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/07 16:06 upstream 602042bf29f6 6520ecdb .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/07 06:25 upstream 69f80fef3153 f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/06 12:34 upstream 2c3418fffa9d f7710056 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/05 13:43 upstream a90ee4305c4a af63e995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/05 04:06 upstream a90ee4305c4a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/04 02:23 upstream a74306e2e676 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/03 10:15 upstream e767a4ea70a3 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/02 05:44 upstream ce1e0223d8ad 6d32eb1f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/10/01 14:08 upstream 551c722f4080 f5cdae2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/09/30 16:42 upstream 551c722f4080 7808aef4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/09/29 20:13 upstream 6f8319e3e9a4 328436b3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/09/29 16:55 upstream 6f8319e3e9a4 7bf4ea23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/09/29 04:21 upstream 72d3fcf802c4 7bf4ea23 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/08/09 08:58 upstream 06cf61899d64 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
2026/08/04 08:45 upstream 848acc8ffe1b 9451e17e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __set_task_comm / strlen
* Struck through repros no longer work on HEAD.