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BUG: KCSAN: data-race in task_participate_group_stop / wait_consider_task

write to 0xffff888149cb44f4 of 4 bytes by task 21649 on cpu 0:
 signal_set_stop_flags include/linux/sched/signal.h:275 [inline]
 task_participate_group_stop+0x18f/0x1e0 kernel/signal.c:381
 do_signal_stop+0x45c/0x5a0 kernel/signal.c:2617
 get_signal+0x689/0xf70 kernel/signal.c:2985
 arch_do_signal_or_restart+0x96/0x480 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x7a/0x100 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x1d6/0x200 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888149cb44f4 of 4 bytes by task 21645 on cpu 1:
 task_stopped_code kernel/exit.c:1289 [inline]
 wait_task_stopped kernel/exit.c:1327 [inline]
 wait_consider_task+0x381/0x1660 kernel/exit.c:1528
 do_wait_thread kernel/exit.c:1554 [inline]
 __do_wait+0xfa/0x510 kernel/exit.c:1672
 do_wait+0xb7/0x260 kernel/exit.c:1706
 kernel_waitid kernel/exit.c:1789 [inline]
 __do_sys_waitid kernel/exit.c:1802 [inline]
 __se_sys_waitid+0xca/0x2a0 kernel/exit.c:1797
 __x64_sys_waitid+0x67/0x80 kernel/exit.c:1797
 x64_sys_call+0xb0d/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:248
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 21645 Comm:  Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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