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BUG: KCSAN: data-race in fasync_remove_entry / kill_fasync

write to 0xffff88810c1d8b00 of 8 bytes by task 16740 on cpu 1:
 fasync_remove_entry+0xd5/0x140 fs/fcntl.c:884
 fasync_helper+0x92/0xc0 fs/fcntl.c:983
 perf_fasync+0x5a/0x80 kernel/events/core.c:6190
 __fput+0x420/0x460 fs/file_table.c:278
 ____fput+0x11/0x20 fs/file_table.c:314
 task_work_run+0x8e/0x110 kernel/task_work.c:123
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:216 [inline]
 __prepare_exit_to_usermode+0x1c6/0x230 arch/x86/entry/common.c:246
 __syscall_return_slowpath+0x47/0x60 arch/x86/entry/common.c:329
 do_syscall_64+0x5d/0xb0 arch/x86/entry/common.c:368
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810c1d8b00 of 8 bytes by interrupt on cpu 0:
 kill_fasync+0x1e/0x160 fs/fcntl.c:1021
 perf_event_wakeup kernel/events/core.c:6230 [inline]
 perf_pending_event+0x258/0x300 kernel/events/core.c:6286
 irq_work_single kernel/irq_work.c:148 [inline]
 irq_work_run_list kernel/irq_work.c:170 [inline]
 irq_work_run+0xf7/0x2c0 kernel/irq_work.c:179
 __sysvec_irq_work+0x22/0xd0 arch/x86/kernel/irq_work.c:22
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 sysvec_irq_work+0x8f/0xe0 arch/x86/kernel/irq_work.c:17
 asm_sysvec_irq_work+0x12/0x20 arch/x86/include/asm/idtentry.h:626
 arch_local_irq_restore arch/x86/include/asm/paravirt.h:765 [inline]
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
 _raw_spin_unlock_irqrestore+0x44/0x70 kernel/locking/spinlock.c:191
 try_to_wake_up+0x2db/0x4d0 kernel/sched/core.c:2665
 wake_up_process kernel/sched/core.c:2733 [inline]
 wake_up_q+0x46/0x80 kernel/sched/core.c:498
 futex_wake+0x365/0x3c0 kernel/futex.c:1642
 do_futex+0xcf8/0x21c0 kernel/futex.c:3816
 __do_sys_futex kernel/futex.c:3872 [inline]
 __se_sys_futex+0x26d/0x330 kernel/futex.c:3840
 __x64_sys_futex+0x74/0x80 kernel/futex.c:3840
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 16748 Comm: syz-executor.5 Not tainted 5.8.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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