syzbot

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BUG: KCSAN: data-race in detach_pid / perf_event_switch_output

write to 0xffff888150a9d5e8 of 8 bytes by task 19592 on cpu 1:
 __change_pid kernel/pid.c:347 [inline]
 detach_pid+0xd7/0x160 kernel/pid.c:358
 __unhash_process kernel/exit.c:75 [inline]
 __exit_signal kernel/exit.c:148 [inline]
 release_task+0x6ff/0xbb0 kernel/exit.c:200
 wait_task_zombie kernel/exit.c:1114 [inline]
 wait_consider_task+0x1078/0x1900 kernel/exit.c:1341
 do_wait_pid kernel/exit.c:1472 [inline]
 do_wait+0x355/0x680 kernel/exit.c:1514
 kernel_wait+0x4e/0xc0 kernel/exit.c:1701
 call_usermodehelper_exec_sync kernel/umh.c:139 [inline]
 call_usermodehelper_exec_work+0x98/0x150 kernel/umh.c:166
 process_one_work+0x3fc/0x980 kernel/workqueue.c:2298
 worker_thread+0x616/0xa70 kernel/workqueue.c:2445
 kthread+0x2c7/0x2e0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30

read to 0xffff888150a9d5e8 of 8 bytes by task 1819 on cpu 0:
 pid_alive include/linux/sched.h:1555 [inline]
 perf_event_pid_type kernel/events/core.c:1411 [inline]
 perf_event_pid kernel/events/core.c:1418 [inline]
 perf_event_switch_output+0x199/0x350 kernel/events/core.c:8686
 perf_iterate_sb_cpu kernel/events/core.c:7605 [inline]
 perf_iterate_sb+0x38d/0x920 kernel/events/core.c:7635
 perf_event_switch kernel/events/core.c:8733 [inline]
 __perf_event_task_sched_in+0x5e1/0x8d0 kernel/events/core.c:3931
 perf_event_task_sched_in include/linux/perf_event.h:1209 [inline]
 finish_task_switch+0x1ef/0x280 kernel/sched/core.c:4847
 context_switch kernel/sched/core.c:4975 [inline]
 __schedule+0x44a/0x6a0 kernel/sched/core.c:6253
 schedule+0x81/0xb0 kernel/sched/core.c:6326
 exit_to_user_mode_loop kernel/entry/common.c:163 [inline]
 exit_to_user_mode_prepare+0xc5/0x190 kernel/entry/common.c:207
 irqentry_exit_to_user_mode+0x5/0x10 kernel/entry/common.c:313
 irqentry_exit+0xe/0x40 kernel/entry/common.c:404
 sysvec_apic_timer_interrupt+0x4a/0xb0 arch/x86/kernel/apic/apic.c:1097
 asm_sysvec_apic_timer_interrupt+0x12/0x20

value changed: 0xffff888146625e80 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1819 Comm: syz-fuzzer Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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