syzbot

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BUG: KCSAN: data-race in do_notify_parent_cldstop / do_signal_stop

write to 0xffff88813556ba20 of 4 bytes by task 9170 on cpu 0:
 do_signal_stop+0xfb/0x700 kernel/signal.c:2425
 get_signal+0xa19/0x15d0 kernel/signal.c:2820
 arch_do_signal_or_restart+0x8c/0x280 arch/x86/kernel/signal.c:865
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x109/0x190 kernel/entry/common.c:207
 irqentry_exit_to_user_mode+0x5/0x10 kernel/entry/common.c:313
 irqentry_exit+0xe/0x30 kernel/entry/common.c:404
 sysvec_apic_timer_interrupt+0x3e/0x80 arch/x86/kernel/apic/apic.c:1097
 asm_sysvec_apic_timer_interrupt+0x12/0x20

read to 0xffff88813556ba20 of 4 bytes by task 9185 on cpu 1:
 do_notify_parent_cldstop+0x1a1/0x290 kernel/signal.c:2140
 get_signal+0x408/0x15d0 kernel/signal.c:2694
 arch_do_signal_or_restart+0x8c/0x280 arch/x86/kernel/signal.c:865
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x109/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000 -> 0x00000014

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 9185 Comm: syz-executor.1 Not tainted 5.15.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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