syzbot

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BUG: KCSAN: data-race in do_notify_parent_cldstop / wait_consider_task

write to 0xffff88812a54c518 of 4 bytes by task 31322 on cpu 0:
 wait_task_stopped kernel/exit.c:1192 [inline]
 wait_consider_task+0xb8b/0x1900 kernel/exit.c:1378
 ptrace_do_wait kernel/exit.c:1418 [inline]
 do_wait+0x1f4/0x680 kernel/exit.c:1525
 kernel_wait4+0x14b/0x1b0 kernel/exit.c:1684
 __do_sys_wait4 kernel/exit.c:1712 [inline]
 __se_sys_wait4 kernel/exit.c:1708 [inline]
 __x64_sys_wait4+0x90/0x120 kernel/exit.c:1708
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88812a54c518 of 4 bytes by task 31321 on cpu 1:
 do_notify_parent_cldstop+0x1c1/0x290
 ptrace_stop+0x28c/0x5d0 kernel/signal.c:2248
 ptrace_do_notify kernel/signal.c:2315 [inline]
 ptrace_notify+0x109/0x160 kernel/signal.c:2325
 ptrace_report_syscall include/linux/tracehook.h:66 [inline]
 tracehook_report_syscall_entry include/linux/tracehook.h:105 [inline]
 arch_syscall_enter_tracehook include/linux/entry-common.h:98 [inline]
 syscall_trace_enter+0x87/0x2b0 kernel/entry/common.c:61
 __syscall_enter_from_user_work kernel/entry/common.c:90 [inline]
 syscall_enter_from_user_mode+0x1c/0x20 kernel/entry/common.c:108
 do_syscall_64+0x25/0xd0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000005 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 31321 Comm: syz-executor.4 Not tainted 5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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