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BUG: KCSAN: data-race in fasync_remove_entry / kill_fasync

write to 0xffff8880b0507ef8 of 8 bytes by task 17456 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:5917
 __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

read to 0xffff8880b0507ef8 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:5957
 perf_pending_event+0x12d/0x170 kernel/events/core.c:6013
 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+0x3f/0x100 arch/x86/kernel/irq_work.c:21
 irq_work_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:861
 up_read+0x25/0xa0 kernel/locking/rwsem.c:1575
 i_mmap_unlock_read include/linux/fs.h:541 [inline]
 rmap_walk_file+0x33e/0x590 mm/rmap.c:1903
 rmap_walk+0x118/0x190 mm/rmap.c:1913
 page_referenced+0x186/0x3b0 mm/rmap.c:875
 page_check_references mm/vmscan.c:1037 [inline]
 shrink_page_list+0xb80/0x26f0 mm/vmscan.c:1270
 reclaim_pages+0x52f/0x6f0 mm/vmscan.c:2188
 madvise_cold_or_pageout_pte_range+0xc29/0x1720 mm/madvise.c:373
 walk_pmd_range mm/pagewalk.c:53 [inline]
 walk_pud_range mm/pagewalk.c:112 [inline]
 walk_p4d_range mm/pagewalk.c:139 [inline]
 walk_pgd_range mm/pagewalk.c:166 [inline]
 __walk_page_range+0x9d8/0xed0 mm/pagewalk.c:261
 walk_page_range+0x133/0x260 mm/pagewalk.c:349
 madvise_pageout_page_range mm/madvise.c:506 [inline]
 madvise_pageout+0x179/0x220 mm/madvise.c:542
 madvise_vma mm/madvise.c:931 [inline]
 __do_sys_madvise+0x548/0x1150 mm/madvise.c:1113
 __se_sys_madvise mm/madvise.c:1039 [inline]
 __x64_sys_madvise+0x4c/0x60 mm/madvise.c:1039
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 17457 Comm: syz-executor.3 Not tainted 5.4.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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