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_read serial				1	922d	922d	0/26	auto-closed as invalid on 2021/11/13 08:12

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BUG: KCSAN: data-race in __tty_hangup / vfs_read

write to 0xffff88813d8e3428 of 8 bytes by task 9801 on cpu 0:
 __tty_hangup+0x1e9/0x560 drivers/tty/tty_io.c:622
 tty_vhangup+0x13/0x20 drivers/tty/tty_io.c:701
 pty_close+0x25e/0x280 drivers/tty/pty.c:79
 tty_release+0x200/0x960 drivers/tty/tty_io.c:1751
 __fput+0x245/0x570 fs/file_table.c:320
 ____fput+0x11/0x20 fs/file_table.c:348
 task_work_run+0xde/0x110 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x124/0x130 kernel/entry/common.c:171
 exit_to_user_mode_prepare kernel/entry/common.c:203 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x6a/0x90 kernel/entry/common.c:296
 do_syscall_64+0x37/0x70 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88813d8e3428 of 8 bytes by task 9800 on cpu 1:
 vfs_read+0x166/0x560 fs/read_write.c:467
 ksys_read+0xe8/0x1a0 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:621
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0xffffffff850b4688 -> 0xffffffff850b4578

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 9800 Comm: syz-executor.1 Not tainted 6.1.0-rc5-syzkaller-00241-gab290eaddc4c-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
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