syzbot

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BUG: KCSAN: data-race in tty_port_open / uart_ioctl

read-write to 0xffff888101a485d8 of 4 bytes by task 21468 on cpu 1:
 tty_port_open+0x3f/0x1f0 drivers/tty/tty_port.c:769
 uart_open+0x2c/0x50 drivers/tty/serial/serial_core.c:1926
 tty_open+0x3e2/0xb00 drivers/tty/tty_io.c:2143
 chrdev_open+0x362/0x3d0 fs/char_dev.c:414
 do_dentry_open+0x59a/0x910 fs/open.c:882
 vfs_open+0x43/0x50 fs/open.c:1013
 do_open fs/namei.c:3557 [inline]
 path_openat+0x16b8/0x1b60 fs/namei.c:3714
 do_filp_open+0x105/0x220 fs/namei.c:3741
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1310
 do_sys_open fs/open.c:1326 [inline]
 __do_sys_openat fs/open.c:1342 [inline]
 __se_sys_openat fs/open.c:1337 [inline]
 __x64_sys_openat+0xef/0x110 fs/open.c:1337
 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

read to 0xffff888101a485d8 of 4 bytes by task 21470 on cpu 0:
 tty_port_users include/linux/tty_port.h:253 [inline]
 uart_do_autoconfig drivers/tty/serial/serial_core.c:1148 [inline]
 uart_ioctl+0x2fd/0x950 drivers/tty/serial/serial_core.c:1529
 tty_ioctl+0x689/0x940 drivers/tty/tty_io.c:2775
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:856
 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: 0x00000009 -> 0x0000000a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 21470 Comm: syz-executor.4 Not tainted 6.2.0-rc6-syzkaller-00003-g22b8077d0fce-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
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