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BUG: KCSAN: data-race in fasync_remove_entry / kill_fasync

write to 0xffff8880a4ffbf00 of 8 bytes by task 9302 on cpu 1:
 fasync_remove_entry+0xb7/0x120 fs/fcntl.c:882
 fasync_helper+0xc9/0xd6 fs/fcntl.c:981
 perf_fasync+0x64/0x90 kernel/events/core.c:6011
 __fput+0x448/0x4f0 fs/file_table.c:277
 ____fput+0x1b/0x30 fs/file_table.c:313
 task_work_run+0xf5/0x130 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2ae/0x2c0 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x36e/0x390 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880a4ffbf00 of 8 bytes by interrupt on cpu 0:
 kill_fasync+0x3c/0x170 fs/fcntl.c:1019
 perf_event_wakeup+0x115/0x160 kernel/events/core.c:6051
 perf_pending_event+0x129/0x170 kernel/events/core.c:6107
 irq_work_run_list+0x13e/0x190 kernel/irq_work.c:156
 irq_work_run+0x43/0x90 kernel/irq_work.c:172
 smp_irq_work_interrupt+0x3b/0xf0 arch/x86/kernel/irq_work.c:21
 irq_work_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:860
 arch_local_irq_enable arch/x86/include/asm/paravirt.h:762 [inline]
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline]
 _raw_spin_unlock_irq+0x4b/0x80 kernel/locking/spinlock.c:199
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers kernel/time/timer.c:1774 [inline]
 __run_timers kernel/time/timer.c:1741 [inline]
 run_timer_softirq+0xb04/0xbd0 kernel/time/timer.c:1787
 __do_softirq+0x118/0x34a kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0xb5/0xd0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:546 [inline]
 smp_apic_timer_interrupt+0xe2/0x270 arch/x86/kernel/apic/apic.c:1146
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 __nr_to_section include/linux/mmzone.h:1254 [inline]
 pfn_valid+0x5f/0x10b include/linux/mmzone.h:1364
 mark_nosave_pages kernel/power/snapshot.c:1059 [inline]
 create_basic_memory_bitmaps.cold+0xba/0x146 kernel/power/snapshot.c:1107
 snapshot_open+0x35f/0x3c0 kernel/power/user.c:88
 misc_open+0x255/0x2b0 drivers/char/misc.c:141
 chrdev_open+0x14a/0x370 fs/char_dev.c:414
 do_dentry_open+0x306/0x970 fs/open.c:797
 vfs_open+0x62/0x80 fs/open.c:914
 do_last fs/namei.c:3490 [inline]
 path_openat+0xdbf/0x2f70 fs/namei.c:3607
 do_filp_open+0x11e/0x1b0 fs/namei.c:3637
 do_sys_openat2+0x4f5/0x620 fs/open.c:1149
 do_sys_open+0xa2/0x110 fs/open.c:1165
 __do_sys_openat fs/open.c:1179 [inline]
 __se_sys_openat fs/open.c:1174 [inline]
 __x64_sys_openat+0x5d/0x70 fs/open.c:1174
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 9311 Comm: syz-executor.0 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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