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BUG: KCSAN: data-race in detach_pid / perf_event_switch_output

write to 0xffff8881018b0660 of 8 bytes by task 16855 on cpu 1:
 __change_pid kernel/pid.c:414 [inline]
 detach_pid+0xf0/0x1a0 kernel/pid.c:426
 __unhash_process kernel/exit.c:140 [inline]
 __exit_signal kernel/exit.c:211 [inline]
 release_task+0x67c/0xb90 kernel/exit.c:272
 wait_task_zombie kernel/exit.c:1291 [inline]
 wait_consider_task+0x10ef/0x15f0 kernel/exit.c:1518
 do_wait_thread kernel/exit.c:1581 [inline]
 __do_wait+0xf1/0x500 kernel/exit.c:1699
 do_wait+0xb6/0x230 kernel/exit.c:1733
 kernel_wait4+0x19f/0x210 kernel/exit.c:1892
 __do_sys_wait4 kernel/exit.c:1920 [inline]
 __se_sys_wait4 kernel/exit.c:1916 [inline]
 __x64_sys_wait4+0x91/0x120 kernel/exit.c:1916
 x64_sys_call+0x108f/0x2550 arch/x86/include/generated/asm/syscalls_64.h:62
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881018b0660 of 8 bytes by task 0 on cpu 0:
 pid_alive include/linux/pid.h:267 [inline]
 perf_event_pid_type kernel/events/core.c:1534 [inline]
 perf_event_tid kernel/events/core.c:1546 [inline]
 perf_event_switch_output+0x1ce/0x3a0 kernel/events/core.c:10113
 perf_iterate_sb_cpu kernel/events/core.c:9039 [inline]
 perf_iterate_sb+0x369/0x650 kernel/events/core.c:9068
 perf_event_switch kernel/events/core.c:10151 [inline]
 __perf_event_task_sched_in+0xa9d/0xb40 kernel/events/core.c:4335
 perf_event_task_sched_in include/linux/perf_event.h:1623 [inline]
 finish_task_switch+0x2bd/0x340 kernel/sched/core.c:5379
 context_switch kernel/sched/core.c:5536 [inline]
 __schedule+0x79e/0xd20 kernel/sched/core.c:7284
 schedule_idle+0x1d/0x40 kernel/sched/core.c:7402
 do_idle+0x27e/0x2d0 kernel/sched/idle.c:384
 cpu_startup_entry+0x24/0x30 kernel/sched/idle.c:454
 rest_init+0x101/0x110 init/main.c:732
 start_kernel+0x49f/0x4d0 init/main.c:1190
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0xfc/0x100 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x157

value changed: 0xffff888140619540 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
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