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BUG: KCSAN: data-race in serial8250_fifo_wait_for_lsr_thre / serial8250_register_8250_port

write to 0xffffffff8962955a of 2 bytes by task 9561 on cpu 1:
 serial8250_register_8250_port+0xead/0x1000 drivers/tty/serial/8250/8250_core.c:894
 serial_pnp_probe+0x405/0x520 drivers/tty/serial/8250/8250_pnp.c:480
 pnp_device_probe+0x1f7/0x2b0 drivers/pnp/driver.c:111
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x1ba/0x600 drivers/base/dd.c:706
 __driver_probe_device+0x14f/0x1c0 drivers/base/dd.c:868
 device_driver_attach+0x8d/0x130 drivers/base/dd.c:1203
 bind_store+0x17b/0x1c0 drivers/base/bus.c:267
 drv_attr_store+0x57/0x80 drivers/base/bus.c:125
 sysfs_kf_write+0xfe/0x120 fs/sysfs/file.c:145
 kernfs_fop_write_iter+0x1d2/0x2e0 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x57f/0x9a0 fs/read_write.c:687
 ksys_write+0xdc/0x1a0 fs/read_write.c:739
 __do_sys_write fs/read_write.c:750 [inline]
 __se_sys_write fs/read_write.c:747 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:747
 x64_sys_call+0x154e/0x2550 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff8962955a of 2 bytes by task 9566 on cpu 0:
 serial_lsr_in drivers/tty/serial/8250/8250.h:151 [inline]
 wait_for_lsr drivers/tty/serial/8250/8250_port.c:2013 [inline]
 serial8250_fifo_wait_for_lsr_thre+0x16f/0x240 drivers/tty/serial/8250/8250_port.c:3270
 __serial8250_console_fifo_write+0x8b/0x1f0 drivers/tty/serial/8250/8250_port.c:3345
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3378 [inline]
 __serial8250_console_write drivers/tty/serial/8250/8250_port.c:3429 [inline]
 serial8250_console_write+0x406/0xac0 drivers/tty/serial/8250/8250_port.c:3493
 univ8250_console_write_thread+0x38/0x50 drivers/tty/serial/8250/8250_core.c:406
 nbcon_emit_next_record+0x10e1/0x1bc0 kernel/printk/nbcon.c:-1
 nbcon_emit_one kernel/printk/nbcon.c:1157 [inline]
 nbcon_kthread_func+0x3fd/0x690 kernel/printk/nbcon.c:1271
 kthread+0x223/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x0000 -> 0x001e

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 9566 Comm: pr/ttyS0 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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