syzbot

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BUG: KCSAN: data-race in perf_event_exit_task / perf_event_exit_task

write to 0xffff8880ab516f0c of 4 bytes by task 22462 on cpu 1:
 perf_event_wakeup kernel/events/core.c:6248 [inline]
 perf_event_exit_event kernel/events/core.c:12272 [inline]
 perf_event_exit_task_context kernel/events/core.c:12331 [inline]
 perf_event_exit_task+0x123b/0x1600 kernel/events/core.c:12364
 do_exit+0x6e4/0x16c0 kernel/exit.c:815
 do_group_exit+0xcb/0x180 kernel/exit.c:903
 get_signal+0xe9f/0x1650 kernel/signal.c:2757
 arch_do_signal+0x25/0x270 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:136 [inline]
 exit_to_user_mode_prepare+0x124/0x210 kernel/entry/common.c:167
 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:242
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880ab516f0c of 4 bytes by task 22454 on cpu 0:
 perf_event_wakeup kernel/events/core.c:6246 [inline]
 perf_event_exit_event kernel/events/core.c:12252 [inline]
 perf_event_exit_task_context kernel/events/core.c:12331 [inline]
 perf_event_exit_task+0x13a4/0x1600 kernel/events/core.c:12364
 do_exit+0x6e4/0x16c0 kernel/exit.c:815
 do_group_exit+0xcb/0x180 kernel/exit.c:903
 get_signal+0xe9f/0x1650 kernel/signal.c:2757
 arch_do_signal+0x25/0x270 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:136 [inline]
 exit_to_user_mode_prepare+0x124/0x210 kernel/entry/common.c:167
 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:242
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 22454 Comm: syz-executor.4 Not tainted 5.9.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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