KCSAN: data-race in __tty_hangup / vfs

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __tty_hangup / vfs_write serial				1	1239d	1239d	0/28	auto-closed as invalid on 2021/10/12 13:22

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BUG: KCSAN: data-race in __tty_hangup / vfs_write

write to 0xffff8881367f84b0 of 8 bytes by task 31389 on cpu 0:
 __tty_hangup+0x1e8/0x520 drivers/tty/tty_io.c:623
 tty_vhangup drivers/tty/tty_io.c:702 [inline]
 tty_ioctl+0x60a/0xbc0 drivers/tty/tty_io.c:2726
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xcf/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff8881367f84b0 of 8 bytes by task 31387 on cpu 1:
 call_write_iter include/linux/fs.h:1871 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x491/0x7d0 fs/read_write.c:584
 ksys_write+0xeb/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0xffffffff84e92bb0 -> 0xffffffff84e92a40

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 31387 Comm: syz-executor.0 Not tainted 6.5.0-rc4-syzkaller-00174-gc1a515d3c027 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
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