CVE-2022-49309: drivers: staging: rtl8723bs: Fix deadlock in rtw_surveydone_event_callback()

Vulnerability summary

CVE-2022-49309 is a medium (CVSS 5.5) Improper Locking vulnerability in linux. EPSS estimates a 0.20% chance of exploitation in the next 30 days, higher than 9.7% of scored vulnerabilities.

Timeline

1. 26-02-2025
   PublishedVulnerability first disclosed.
2. 12-08-2026
   Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: drivers: staging: rtl8723bs: Fix deadlock in rtw_surveydone_event_callback() There is a deadlock in rtw_surveydone_event_callback(), which is shown below: (Thread 1) | (Thread 2) | _set_timer() rtw_surveydone_event_callback()| mod_timer() spin_lock_bh() //(1) | (wait a time) ... | rtw_scan_timeout_handler() del_timer_sync() | spin_lock_bh() //(2) (wait timer to stop) | ... We hold pmlmepriv->lock in position (1) of thread 1 and use del_timer_sync() to wait timer to stop, but timer handler also need pmlmepriv->lock in position (2) of thread 2. As a result, rtw_surveydone_event_callback() will block forever. This patch extracts del_timer_sync() from the protection of spin_lock_bh(), which could let timer handler to obtain the needed lock. What`s more, we change spin_lock_bh() in rtw_scan_timeout_handler() to spin_lock_irq(). Otherwise, spin_lock_bh() will also cause deadlock() in timer handler.

• CWE-667Improper LockingThe product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.