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BUG: KCSAN: data-race in __set_task_comm / strlen

write to 0xffff888104b0ccd8 of 10 bytes by task 8633 on cpu 0:
 __set_task_comm+0x78/0x180 fs/exec.c:1099
 __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+0x2533/0x3020 arch/x86/include/generated/asm/syscalls_64.h:158
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888104b0ccdf of 1 bytes by task 4292 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+0x59/0x140 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+0x153/0x460 kernel/sched/fair.c:1375
 update_curr+0x29/0x210 kernel/sched/fair.c:2001
 enqueue_entity kernel/sched/fair.c:6121 [inline]
 enqueue_task_fair+0x144/0xab0 kernel/sched/fair.c:7857
 enqueue_task kernel/sched/core.c:2184 [inline]
 activate_task kernel/sched/core.c:2224 [inline]
 ttwu_do_activate+0xa7/0x230 kernel/sched/core.c:3824
 ttwu_queue kernel/sched/core.c:4077 [inline]
 try_to_wake_up+0x44a/0x6c0 kernel/sched/core.c:4415
 ep_autoremove_wake_function+0x2c/0xb0 fs/eventpoll.c:2204
 __wake_up_common kernel/sched/wait.c:108 [inline]
 __wake_up_common_lock kernel/sched/wait.c:125 [inline]
 __wake_up+0x66/0xb0 kernel/sched/wait.c:146
 ep_poll_callback+0x448/0x590 fs/eventpoll.c:1564
 __wake_up_common kernel/sched/wait.c:108 [inline]
 __wake_up_common_lock kernel/sched/wait.c:125 [inline]
 __wake_up+0x66/0xb0 kernel/sched/wait.c:146
 fsnotify_insert_event+0x206/0x240 fs/notify/notification.c:127
 fsnotify_add_event include/linux/fsnotify_backend.h:759 [inline]
 inotify_handle_inode_event+0x31d/0x3c0 fs/notify/inotify/inotify_fsnotify.c:126
 inotify_ignored_and_remove_idr+0x29/0x60 fs/notify/inotify/inotify_user.c:526
 inotify_freeing_mark+0x1d/0x30 fs/notify/inotify/inotify_fsnotify.c:140
 fsnotify_free_mark fs/notify/mark.c:659 [inline]
 fsnotify_destroy_mark+0x123/0x140 fs/notify/mark.c:668
 __do_sys_inotify_rm_watch fs/notify/inotify/inotify_user.c:806 [inline]
 __se_sys_inotify_rm_watch+0xe8/0x170 fs/notify/inotify/inotify_user.c:787
 __x64_sys_inotify_rm_watch+0x31/0x40 fs/notify/inotify/inotify_user.c:787
 x64_sys_call+0xc88/0x3020 arch/x86/include/generated/asm/syscalls_64.h:256
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x63 -> 0x33

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 4292 Comm: udevd Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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