KCSAN: data-race in do_notify_parent_cldstop / wait_consider

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in do_notify_parent_cldstop / wait_consider_task kernel				60	904d	953d	0/26	auto-closed as invalid on 2021/12/17 00:39

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BUG: KCSAN: data-race in do_notify_parent_cldstop / wait_consider_task

write to 0xffff88810750d370 of 4 bytes by task 27505 on cpu 1:
 wait_task_stopped kernel/exit.c:1189 [inline]
 wait_consider_task+0xabe/0x1700 kernel/exit.c:1375
 ptrace_do_wait kernel/exit.c:1415 [inline]
 do_wait+0x1f4/0x670 kernel/exit.c:1522
 kernel_wait4+0x14b/0x1b0 kernel/exit.c:1681
 __do_sys_wait4 kernel/exit.c:1709 [inline]
 __se_sys_wait4 kernel/exit.c:1705 [inline]
 __x64_sys_wait4+0x90/0x120 kernel/exit.c:1705
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88810750d370 of 4 bytes by task 27509 on cpu 0:
 do_notify_parent_cldstop+0x1a0/0x290 kernel/signal.c:2175
 ptrace_stop+0x2e6/0x610 kernel/signal.c:2293
 ptrace_signal+0x52/0x250 kernel/signal.c:2570
 get_signal+0x848/0x1020 kernel/signal.c:2745
 arch_do_signal_or_restart+0x87/0x2d0 arch/x86/kernel/signal.c:869
 exit_to_user_mode_loop+0x78/0x130 kernel/entry/common.c:166
 exit_to_user_mode_prepare+0x69/0x90 kernel/entry/common.c:201
 irqentry_exit_to_user_mode+0x5/0x10 kernel/entry/common.c:307
 irqentry_exit+0xe/0x40 kernel/entry/common.c:408
 asm_exc_page_fault+0x22/0x30

value changed: 0x00000013 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 27509 Comm: syz-executor.3 Not tainted 5.19.0-syzkaller-13215-geb555cb5b794-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
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