CVE-2023-53848 md/raid5-cache: fix a deadlock in r5l_exit_log()
A deadlock in the Linux kernel's RAID5 cache module can cause a denial of service when exiting the log.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-53848?
CVE-2023-53848 is a denial of service vulnerability in Linux, published on 9 Dec 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:
md/raid5-cache: fix a deadlock in r5l_exit_log()
Commit b13015af94cf ("md/raid5-cache: Clear conf->log after finishing work") introduce a new problem:
// caller hold reconfig_mutex r5l_exit_log flush_work(&log->disable_writeback_work) r5c_disable_writeback_async wait_event /* * conf->log is not NULL, and mddev_trylock() * will fail, wait_event() can never pass. */ conf->log = NULL
Fix this problem by setting 'config->log' to NULL before wake_up() as it used to be, so that wait_event() from r5c_disable_writeback_async() can exist. In the meantime, move forward md_unregister_thread() so that null-ptr-deref this commit fixed can still be fixed.
Which versions are affected by CVE-2023-53848?
How do I fix CVE-2023-53848?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2023-53848 being exploited?
There is no known exploitation of CVE-2023-53848 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-53848, DEBIAN-CVE-2023-53848, GHSA-j393-rh49-r5p6, UBUNTU-CVE-2023-53848.