KCSAN: data-race in __io_arm_poll_handler / __tty

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __io_arm_poll_handler / __tty_hangup (2) serial				1	5d09h	5d09h	0/28	moderation: reported on 2025/06/04 17:59

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BUG: KCSAN: data-race in __io_arm_poll_handler / __tty_hangup

write to 0xffff88813b21f8b0 of 8 bytes by task 23199 on cpu 1:
 __tty_hangup+0x1e8/0x530 drivers/tty/tty_io.c:621
 tty_vhangup+0x17/0x20 drivers/tty/tty_io.c:700
 pty_close+0x262/0x280 drivers/tty/pty.c:79
 tty_release+0x204/0x930 drivers/tty/tty_io.c:1756
 __fput+0x299/0x630 fs/file_table.c:394
 __fput_sync+0x44/0x50 fs/file_table.c:475
 __do_sys_close fs/open.c:1590 [inline]
 __se_sys_close+0xfa/0x1a0 fs/open.c:1575
 __x64_sys_close+0x1f/0x30 fs/open.c:1575
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff88813b21f8b0 of 8 bytes by task 23201 on cpu 0:
 vfs_poll include/linux/poll.h:86 [inline]
 __io_arm_poll_handler+0x1df/0xe30 io_uring/poll.c:600
 io_arm_poll_handler+0x426/0x580 io_uring/poll.c:735
 io_queue_async+0x85/0x470 io_uring/io_uring.c:2048
 io_queue_sqe io_uring/io_uring.c:2079 [inline]
 io_req_task_submit+0x11c/0x130 io_uring/io_uring.c:1498
 io_poll_task_func+0x722/0x800
 handle_tw_list io_uring/io_uring.c:1207 [inline]
 tctx_task_work+0x1af/0x4c0 io_uring/io_uring.c:1299
 task_work_run+0x135/0x1a0 kernel/task_work.c:180
 get_signal+0xf04/0x10a0 kernel/signal.c:2680
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:309
 exit_to_user_mode_loop+0x6f/0xe0 kernel/entry/common.c:168
 exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:296
 do_syscall_64+0x50/0x110 arch/x86/entry/common.c:88
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0xffffffff84e96298 -> 0xffffffff84e96130

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 23201 Comm: syz-executor.3 Not tainted 6.7.0-rc2-syzkaller-00242-g090472ed9c92 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
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