syzbot

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BUG: KCSAN: data-race in task_participate_group_stop / wait_consider_task

write to 0xffff8882091996f4 of 4 bytes by task 18687 on cpu 0:
 signal_set_stop_flags include/linux/sched/signal.h:273 [inline]
 task_participate_group_stop+0x18c/0x1e0 kernel/signal.c:377
 do_signal_stop+0x4c3/0x600 kernel/signal.c:2487
 get_signal+0x5f5/0x10a0 kernel/signal.c:2845
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:105 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline]
 syscall_exit_to_user_mode+0x58/0x130 kernel/entry/common.c:212
 do_syscall_64+0xda/0x1d0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff8882091996f4 of 4 bytes by task 18685 on cpu 1:
 wait_task_continued kernel/exit.c:1316 [inline]
 wait_consider_task+0x12e6/0x1680 kernel/exit.c:1459
 do_wait_pid kernel/exit.c:1552 [inline]
 __do_wait+0x32e/0x4f0 kernel/exit.c:1587
 do_wait+0xae/0x270 kernel/exit.c:1628
 kernel_wait4+0x15f/0x1c0 kernel/exit.c:1787
 __do_sys_wait4 kernel/exit.c:1815 [inline]
 __se_sys_wait4 kernel/exit.c:1811 [inline]
 __x64_sys_wait4+0x94/0x120 kernel/exit.c:1811
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18685 Comm: syz-executor.2 Not tainted 6.8.0-rc3-syzkaller-00279-g4a7bbe7519b6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
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