CVE-2022-49889: ring-buffer: Check for NULL cpu_buffer in ring_buffer_wake_waiters()
First published: Thu May 01 2025(Updated: )
In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Check for NULL cpu_buffer in ring_buffer_wake_waiters() On some machines the number of listed CPUs may be bigger than the actual CPUs that exist. The tracing subsystem allocates a per_cpu directory with access to the per CPU ring buffer via a cpuX file. But to save space, the ring buffer will only allocate buffers for online CPUs, even though the CPU array will be as big as the nr_cpu_ids. With the addition of waking waiters on the ring buffer when closing the file, the ring_buffer_wake_waiters() now needs to make sure that the buffer is allocated (with the irq_work allocated with it) before trying to wake waiters, as it will cause a NULL pointer dereference. While debugging this, I added a NULL check for the buffer itself (which is OK to do), and also NULL pointer checks against buffer->buffers (which is not fine, and will WARN) as well as making sure the CPU number passed in is within the nr_cpu_ids (which is also not fine if it isn't). Bugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=1204705
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | ||
| Linux Kernel | >=5.15.75<5.15.78 | |
| Linux Kernel | >=5.19.17<6.0 | |
| Linux Kernel | >=6.0.3<6.0.8 |
Never miss a vulnerability like this again
Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.
Reference Links
Frequently Asked Questions
What is the severity of CVE-2022-49889?
CVE-2022-49889 has a medium severity rating due to its potential impact on system stability.
How do I fix CVE-2022-49889?
You can fix CVE-2022-49889 by updating the Linux kernel to the latest stable version that includes the patch.
What systems are affected by CVE-2022-49889?
CVE-2022-49889 affects the Linux kernel across various distributions where the tracing subsystem utilizes per-CPU directories.
What type of vulnerability is CVE-2022-49889?
CVE-2022-49889 is a memory management vulnerability related to null pointer dereferences in the ring buffer.
Is CVE-2022-49889 being actively exploited?
As of now, there are no known active exploits for CVE-2022-49889, but users are advised to apply updates promptly.
- agent/weakness
- agent/title
- agent/references
- agent/description
- agent/first-publish-date
- agent/type
- agent/guess-ai
- agent/software-canonical-lookup
- agent/author
- agent/source
- agent/tags
- collector/mitre-cve
- source/MITRE
- agent/severity
- agent/last-modified-date
- agent/remedy
- agent/softwarecombine
- agent/event
- collector/nvd-api
- source/NVD
- vendor/linux
- canonical/linux kernel
- version/linux kernel/5.15.75
- version/linux kernel/5.19.17
- version/linux kernel/6.0.3