CVE-2022-49309 drivers: staging: rtl8723bs: Fix deadlock in rtw_surveydone_event_callback()
A race condition in the rtl8723bs Wi-Fi driver causes a deadlock, leading to a denial of service in the Linux kernel.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-49309?
CVE-2022-49309 is a medium-severity vulnerability in Linux kernel, published on 26 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Weakness: CWE-667
Which versions are affected by CVE-2022-49309?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-49309?
Apply the vendor's patch.
Is CVE-2022-49309 being exploited?
There is no known exploitation of CVE-2022-49309 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-49309, GHSA-xpwf-pw24-jcwf, UBUNTU-CVE-2022-49309.