==================================================================
BUG: KCSAN: data-race in fasync_remove_entry / kill_fasync

read to 0xffff888122b16af8 of 8 bytes by interrupt on cpu 1:
 kill_fasync+0x3f/0x180 fs/fcntl.c:1019
 perf_event_wakeup+0x11f/0x160 kernel/events/core.c:5955
 perf_pending_event+0x12d/0x170 kernel/events/core.c:6011
 irq_work_run_list+0xea/0x140 kernel/irq_work.c:165
 irq_work_run+0x48/0xa0 kernel/irq_work.c:180
 smp_irq_work_interrupt+0x71/0x1c0 arch/x86/kernel/irq_work.c:21
 irq_work_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:861
 find_watchpoint kernel/kcsan/core.c:63 [inline]
 __kcsan_check_watchpoint+0x70/0x180 kernel/kcsan/core.c:266
 __tsan_write4+0x18/0x40 kernel/kcsan/kcsan.c:35
 get_futex_value_locked+0x6b/0xc0 kernel/futex.c:794
 futex_wait_setup+0xe8/0x210 kernel/futex.c:2681
 futex_wait+0x163/0x3f0 kernel/futex.c:2728
 do_futex+0xe9/0x18d0 kernel/futex.c:3644
 __do_sys_futex kernel/futex.c:3705 [inline]
 __se_sys_futex kernel/futex.c:3673 [inline]
 __x64_sys_futex+0x2cd/0x3f0 kernel/futex.c:3673

write to 0xffff888122b16af8 of 8 bytes by task 3328 on cpu 0:
 fasync_remove_entry+0xba/0x120 fs/fcntl.c:882
 fasync_helper+0xcf/0xdc fs/fcntl.c:981
 perf_fasync+0x6c/0xa0 kernel/events/core.c:5915
 __fput+0x46a/0x520 fs/file_table.c:277
 ____fput+0x1f/0x30 fs/file_table.c:313
 task_work_run+0xf6/0x130 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2b4/0x2c0 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
 do_syscall_64+0x353/0x370 arch/x86/entry/common.c:300
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3328 Comm: syz-executor.2 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================