syzbot

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BUG: KCSAN: data-race in __set_task_comm / strlen

write to 0xffff88810c8bc978 of 8 bytes by task 9070 on cpu 0:
 __set_task_comm+0x4d/0x140 fs/exec.c:1088
 begin_new_exec+0xede/0x1280 fs/exec.c:1246
 load_elf_binary+0x62b/0x1a20 fs/binfmt_elf.c:1010
 search_binary_handler fs/exec.c:1669 [inline]
 exec_binprm fs/exec.c:1701 [inline]
 bprm_execve+0x477/0x9b0 fs/exec.c:1753
 kernel_execve+0x617/0x660 fs/exec.c:1919
 call_usermodehelper_exec_async+0x197/0x250 kernel/umh.c:109
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

read to 0xffff88810c8bc978 of 1 bytes by task 9064 on cpu 1:
 strlen+0x19/0x40 lib/string.c:420
 __fortify_strlen include/linux/fortify-string.h:268 [inline]
 trace_event_get_offsets_sched_stat_runtime include/trace/events/sched.h:553 [inline]
 do_perf_trace_sched_stat_runtime include/trace/events/sched.h:553 [inline]
 perf_trace_sched_stat_runtime+0x3c/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+0x129/0x140 kernel/sched/fair.c:1159
 update_curr+0x2c/0x150 kernel/sched/fair.c:1209
 enqueue_entity kernel/sched/fair.c:5225 [inline]
 enqueue_task_fair+0x140/0x970 kernel/sched/fair.c:6929
 enqueue_task kernel/sched/core.c:2094 [inline]
 activate_task+0x59/0xb0 kernel/sched/core.c:2135
 ttwu_do_activate+0x6c/0x210 kernel/sched/core.c:3631
 ttwu_queue kernel/sched/core.c:3894 [inline]
 try_to_wake_up+0x38e/0x640 kernel/sched/core.c:4218
 wake_up_process kernel/sched/core.c:4349 [inline]
 wake_up_q+0x48/0x80 kernel/sched/core.c:1087
 futex_wake+0x2f1/0x360 kernel/futex/waitwake.c:198
 do_futex+0x323/0x380 kernel/futex/syscalls.c:135
 __do_sys_futex kernel/futex/syscalls.c:207 [inline]
 __se_sys_futex+0x2ed/0x360 kernel/futex/syscalls.c:188
 __x64_sys_futex+0x78/0x90 kernel/futex/syscalls.c:188
 x64_sys_call+0x2bc2/0x3000 arch/x86/include/generated/asm/syscalls_64.h:203
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd8/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x6b -> 0x6d

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 9064 Comm: syz.5.1759 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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