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BUG: KCSAN: data-race in fasync_remove_entry / kill_fasync

write to 0xffff888104a10a38 of 8 bytes by task 12407 on cpu 0:
 fasync_remove_entry+0xd5/0x140 fs/fcntl.c:895
 fasync_helper+0x92/0xc0 fs/fcntl.c:994
 vcs_fasync+0x46/0x90 drivers/tty/vt/vc_screen.c:741
 __fput+0x4dd/0x520 fs/file_table.c:308
 ____fput+0x11/0x20 fs/file_table.c:344
 task_work_run+0x8e/0x110 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x160/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888104a10a38 of 8 bytes by task 12433 on cpu 1:
 kill_fasync+0x20/0x160 fs/fcntl.c:1033
 vcs_notifier+0xfe/0x120 drivers/tty/vt/vc_screen.c:114
 notifier_call_chain kernel/notifier.c:84 [inline]
 atomic_notifier_call_chain+0x63/0xc0 kernel/notifier.c:199
 notify_update drivers/tty/vt/vt.c:270 [inline]
 do_con_write+0x5eca/0x5f40 drivers/tty/vt/vt.c:2964
 con_write+0x20/0x40 drivers/tty/vt/vt.c:3295
 process_output_block drivers/tty/n_tty.c:581 [inline]
 n_tty_write+0x77b/0xaf0 drivers/tty/n_tty.c:2250
 do_tty_write drivers/tty/tty_io.c:1024 [inline]
 file_tty_write+0x409/0x660 drivers/tty/tty_io.c:1095
 tty_write+0x24/0x30 drivers/tty/tty_io.c:1116
 call_write_iter include/linux/fs.h:2074 [inline]
 new_sync_write fs/read_write.c:503 [inline]
 vfs_write+0x7f5/0x950 fs/read_write.c:590
 ksys_write+0xd9/0x190 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:652
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffff888136b92750 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 12433 Comm: syz-executor.1 Not tainted 5.17.0-rc2-syzkaller-00353-g90c9e950c0de-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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