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Unrated severityNVD Advisory· Published May 1, 2025· Updated Oct 1, 2025

ring-buffer: Check for NULL cpu_buffer in ring_buffer_wake_waiters()

CVE-2022-49889

Description

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

Affected products

136

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

3

News mentions

0

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