syzbot

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BUG: KCSAN: data-race in perf_event_wakeup / perf_event_wakeup

write to 0xffff88811feacf0c of 4 bytes by task 14909 on cpu 0:
 perf_event_wakeup+0x11d/0x160 kernel/events/core.c:6228
 perf_event_exit_event kernel/events/core.c:12143 [inline]
 perf_event_exit_task_context kernel/events/core.c:12202 [inline]
 perf_event_exit_task+0x63a/0x870 kernel/events/core.c:12235
 do_exit+0x70f/0x11e0 kernel/exit.c:805
 do_group_exit+0xae/0x1a0 kernel/exit.c:893
 get_signal+0x2a7/0x1290 kernel/signal.c:2739
 do_signal+0x2b/0x840 arch/x86/kernel/signal.c:784
 exit_to_usermode_loop+0x24a/0x2c0 arch/x86/entry/common.c:161
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x38b/0x3b0 arch/x86/entry/common.c:305
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88811feacf0c of 4 bytes by task 14910 on cpu 1:
 perf_event_wakeup+0xc7/0x160 kernel/events/core.c:6226
 perf_event_exit_event kernel/events/core.c:12143 [inline]
 perf_event_exit_task_context kernel/events/core.c:12202 [inline]
 perf_event_exit_task+0x63a/0x870 kernel/events/core.c:12235
 do_exit+0x70f/0x11e0 kernel/exit.c:805
 do_group_exit+0xae/0x1a0 kernel/exit.c:893
 get_signal+0x2a7/0x1290 kernel/signal.c:2739
 do_signal+0x2b/0x840 arch/x86/kernel/signal.c:784
 exit_to_usermode_loop+0x24a/0x2c0 arch/x86/entry/common.c:161
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x38b/0x3b0 arch/x86/entry/common.c:305
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 14910 Comm: syz-executor.2 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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