CVE-2022-49304: drivers: tty: serial: Fix deadlock in sa1100_set_termios()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-02-26 · updated 2026-06-17
Weakness: CWE-667

Description

In the Linux kernel, the following vulnerability has been resolved: drivers: tty: serial: Fix deadlock in sa1100_set_termios() There is a deadlock in sa1100_set_termios(), which is shown below: (Thread 1) | (Thread 2) | sa1100_enable_ms() sa1100_set_termios() | mod_timer() spin_lock_irqsave() //(1) | (wait a time) ... | sa1100_timeout() del_timer_sync() | spin_lock_irqsave() //(2) (wait timer to stop) | ... We hold sport->port.lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need sport->port.lock in position (2) of thread 2. As a result, sa1100_set_termios() will block forever. This patch moves del_timer_sync() before spin_lock_irqsave() in order to prevent the deadlock.

Affected products

Linux kernel: before 4.9.318; from 4.10 before 4.14.283; from 4.15 before 4.19.247; from 4.20 before 5.4.198; from 5.5 before 5.10.122; from 5.11 before 5.15.47 — fixed in 4.14.283, 4.19.247, 4.9.318, 5.10.122, 5.15.47, 5.17.15

How to fix

Upgrade to a fixed version: Linux kernel 4.14.283, 4.19.247, 4.9.318, 5.10.122. Check the vendor advisory for mitigations.

References

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