syzbot

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BUG: KCSAN: data-race in __tty_hangup / io_poll_task_func

write to 0xffff888123a03308 of 8 bytes by task 6633 on cpu 0:
 __tty_hangup+0x1c2/0x510 drivers/tty/tty_io.c:615
 tty_vhangup+0x17/0x20 drivers/tty/tty_io.c:694
 pty_close+0x266/0x290 drivers/tty/pty.c:79
 tty_release+0x1ff/0xb10 drivers/tty/tty_io.c:1754
 __fput+0x29b/0x650 fs/file_table.c:465
 ____fput+0x1c/0x30 fs/file_table.c:493
 task_work_run+0x131/0x1a0 kernel/task_work.c:227
 resume_user_mode_work+0x6a/0x70 include/linux/resume_user_mode.h:50
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x77/0xb0 kernel/entry/common.c:218
 do_syscall_64+0xdd/0x1a0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888123a03308 of 8 bytes by task 6636 on cpu 1:
 vfs_poll include/linux/poll.h:80 [inline]
 io_poll_check_events io_uring/poll.c:262 [inline]
 io_poll_task_func+0x114/0xa20 io_uring/poll.c:319
 io_handle_tw_list+0xcc/0x1c0 io_uring/io_uring.c:1049
 tctx_task_work_run+0x6d/0x1a0 io_uring/io_uring.c:1114
 tctx_task_work+0x3f/0x80 io_uring/io_uring.c:1132
 task_work_run+0x131/0x1a0 kernel/task_work.c:227
 get_signal+0xe13/0xf70 kernel/signal.c:2807
 arch_do_signal_or_restart+0x97/0x480 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x68/0xb0 kernel/entry/common.c:218
 do_syscall_64+0xdd/0x1a0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffffffff8589eb18 -> 0xffffffff8589ea10

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 6636 Comm: syz.3.1116 Not tainted 6.15.0-rc6-syzkaller-00052-g9f35e33144ae #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
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