syzbot

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BUG: KCSAN: data-race in do_notify_parent_cldstop / do_signal_stop

write to 0xffff888100fae4e0 of 4 bytes by task 12822 on cpu 0:
 do_signal_stop+0x100/0x6b0 kernel/signal.c:2340
 get_signal+0xa83/0x1510 kernel/signal.c:2718
 arch_do_signal+0x25/0x260 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:161 [inline]
 exit_to_user_mode_prepare+0xde/0x170 kernel/entry/common.c:191
 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:266
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888100fae4e0 of 4 bytes by task 12798 on cpu 1:
 do_notify_parent_cldstop+0x1a1/0x290 kernel/signal.c:2055
 get_signal+0x44c/0x1510 kernel/signal.c:2592
 arch_do_signal+0x25/0x260 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:161 [inline]
 exit_to_user_mode_prepare+0xde/0x170 kernel/entry/common.c:191
 irqentry_exit_to_user_mode+0x5/0x20 kernel/entry/common.c:279
 irqentry_exit+0xe/0x40 kernel/entry/common.c:367
 asm_sysvec_reschedule_ipi+0x12/0x20 arch/x86/include/asm/idtentry.h:636

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 12798 Comm: syz-executor.2 Not tainted 5.10.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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