CVE-2025-38262

In the Linux kernel, the following vulnerability has been resolved:

tty: serial: uartlite: register uart driver in init

When two instances of uart devices are probing, a concurrency race can

occur. If one thread calls uart_register_driver function, which first

allocates and assigns memory to 'uart_state' member of uart_driver

structure, the other instance can bypass uart driver registration and

call ulite_assign. This calls uart_add_one_port, which expects the uart

driver to be fully initialized. This leads to a kernel panic due to a

null pointer dereference:

[ 8.143581] BUG: kernel NULL pointer dereference, address: 00000000000002b8

[ 8.156982] #PF: supervisor write access in kernel mode

[ 8.156984] #PF: error_code(0x0002) - not-present page

[ 8.156986] PGD 0 P4D 0

...

[ 8.180668] RIP: 0010:mutex_lock+0x19/0x30

[ 8.188624] Call Trace:

[ 8.188629] ? __die_body.cold+0x1a/0x1f

[ 8.195260] ? page_fault_oops+0x15c/0x290

[ 8.209183] ? __irq_resolve_mapping+0x47/0x80

[ 8.209187] ? exc_page_fault+0x64/0x140

[ 8.209190] ? asm_exc_page_fault+0x22/0x30

[ 8.209196] ? mutex_lock+0x19/0x30

[ 8.223116] uart_add_one_port+0x60/0x440

[ 8.223122] ? proc_tty_register_driver+0x43/0x50

[ 8.223126] ? tty_register_driver+0x1ca/0x1e0

[ 8.246250] ulite_probe+0x357/0x4b0 [uartlite]

To prevent it, move uart driver registration in to init function. This

will ensure that uart_driver is always registered when probe function

is called.