CVE-2024-40918

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

parisc: Try to fix random segmentation faults in package builds

PA-RISC systems with PA8800 and PA8900 processors have had problems

with random segmentation faults for many years. Systems with earlier

processors are much more stable.

Systems with PA8800 and PA8900 processors have a large L2 cache which

needs per page flushing for decent performance when a large range is

flushed. The combined cache in these systems is also more sensitive to

non-equivalent aliases than the caches in earlier systems.

The majority of random segmentation faults that I have looked at

appear to be memory corruption in memory allocated using mmap and

malloc.

My first attempt at fixing the random faults didn't work. On

reviewing the cache code, I realized that there were two issues

which the existing code didn't handle correctly. Both relate

to cache move-in. Another issue is that the present bit in PTEs

is racy.

1) PA-RISC caches have a

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References