syzbot

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BUG: KCSAN: data-race in do_notify_parent_cldstop / do_signal_stop

write to 0xffff8880622f6aa0 of 4 bytes by task 1010 on cpu 0:
 do_signal_stop+0x100/0x6e0 kernel/signal.c:2340
 get_signal+0x65d/0x14e0 kernel/signal.c:2733
 arch_do_signal_or_restart+0x2a/0x270 arch/x86/kernel/signal.c:811
 handle_signal_work kernel/entry/common.c:147 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x11a/0x1b0 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:294
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880622f6aa0 of 4 bytes by task 979 on cpu 1:
 do_notify_parent_cldstop+0x1a1/0x290 kernel/signal.c:2055
 get_signal+0x10ee/0x14e0 kernel/signal.c:2607
 arch_do_signal_or_restart+0x2a/0x270 arch/x86/kernel/signal.c:811
 handle_signal_work kernel/entry/common.c:147 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x11a/0x1b0 kernel/entry/common.c:201
 irqentry_exit_to_user_mode+0x5/0x20 kernel/entry/common.c:307
 irqentry_exit+0xe/0x40 kernel/entry/common.c:395
 asm_sysvec_reschedule_ipi+0x12/0x20 arch/x86/include/asm/idtentry.h:634

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 979 Comm: syz-executor.0 Not tainted 5.11.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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