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BUG: KCSAN: data-race in fasync_remove_entry / kill_fasync

write to 0xffff888063664f00 of 8 bytes by task 24886 on cpu 0:
 fasync_remove_entry+0xb7/0x120 fs/fcntl.c:884
 fasync_helper+0xc9/0xd6 fs/fcntl.c:983
 perf_fasync+0x64/0x90 kernel/events/core.c:6187
 __fput+0x455/0x500 fs/file_table.c:277
 ____fput+0x1b/0x30 fs/file_table.c:313
 task_work_run+0xba/0x120 kernel/task_work.c:123
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2ae/0x2c0 arch/x86/entry/common.c:165
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x38b/0x3b0 arch/x86/entry/common.c:305
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888063664f00 of 8 bytes by interrupt on cpu 1:
 kill_fasync+0x3c/0x170 fs/fcntl.c:1021
 perf_event_wakeup+0x115/0x160 kernel/events/core.c:6227
 perf_pending_event+0x129/0x170 kernel/events/core.c:6283
 irq_work_run_list+0x13e/0x190 kernel/irq_work.c:157
 irq_work_run+0x43/0x90 kernel/irq_work.c:174
 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
 is_atomic kernel/kcsan/core.c:244 [inline]
 should_watch kernel/kcsan/core.c:257 [inline]
 check_access kernel/kcsan/core.c:581 [inline]
 __tsan_read4+0xd4/0x110 kernel/kcsan/core.c:769
 __rcu_read_unlock+0x42/0x390 kernel/rcu/tree_plugin.h:393
 rcu_read_unlock include/linux/rcupdate.h:654 [inline]
 percpu_ref_tryget_live include/linux/percpu-refcount.h:285 [inline]
 blk_queue_enter+0x67/0x570 block/blk-core.c:404
 generic_make_request block/blk-core.c:1069 [inline]
 generic_make_request+0x121/0x700 block/blk-core.c:1017
 submit_bio+0x8f/0x3a0 block/blk-core.c:1200
 submit_bh_wbc+0x40d/0x460 fs/buffer.c:3063
 __block_write_full_page+0x4f5/0x8e0 fs/buffer.c:1801
 block_write_full_page+0x1ba/0x1d0 fs/buffer.c:2987
 fat_writepage+0x2b/0x40 fs/fat/inode.c:199
 __mpage_writepage+0x7e3/0xdc0 fs/mpage.c:678
 write_cache_pages+0x400/0xa10 mm/page-writeback.c:2238
 mpage_writepages+0xab/0x180 fs/mpage.c:730
 fat_writepages+0x2a/0x40 fs/fat/inode.c:205
 do_writepages+0x6b/0x170 mm/page-writeback.c:2344
 __filemap_fdatawrite_range+0x1bb/0x220 mm/filemap.c:421
 filemap_write_and_wait_range mm/filemap.c:654 [inline]
 filemap_write_and_wait_range+0xad/0x140 mm/filemap.c:648
 __generic_file_write_iter+0x30a/0x370 mm/filemap.c:3417
 generic_file_write_iter+0x294/0x38e mm/filemap.c:3463
 call_write_iter include/linux/fs.h:1907 [inline]
 do_iter_readv_writev+0x4a7/0x5d0 fs/read_write.c:694
 do_iter_write fs/read_write.c:999 [inline]
 do_iter_write+0x137/0x3a0 fs/read_write.c:980
 vfs_iter_write+0x56/0x80 fs/read_write.c:1040
 iter_file_splice_write+0x530/0x830 fs/splice.c:760
 do_splice_from fs/splice.c:863 [inline]
 direct_splice_actor+0x97/0xb0 fs/splice.c:1037
 splice_direct_to_actor+0x22f/0x540 fs/splice.c:992
 do_splice_direct+0x152/0x1d0 fs/splice.c:1080
 do_sendfile+0x380/0x800 fs/read_write.c:1521
 __do_sys_sendfile64 fs/read_write.c:1582 [inline]
 __se_sys_sendfile64 fs/read_write.c:1568 [inline]
 __x64_sys_sendfile64+0x121/0x140 fs/read_write.c:1568
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 24887 Comm: syz-executor.3 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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