CVE-2024-58042

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

rhashtable: Fix potential deadlock by moving schedule_work outside lock

Move the hash table growth check and work scheduling outside the rht lock to prevent a possible circular locking dependency.

The original implementation could trigger a lockdep warning due to a potential deadlock scenario involving nested locks between rhashtable bucket, rq lock, and dsq lock. By relocating the growth check and work scheduling after releasing the rth lock, we break this potential deadlock chain.

This change expands the flexibility of rhashtable by removing restrictive locking that previously limited its use in scheduler and workqueue contexts.

Import to say that this calls rht_grow_above_75(), which reads from struct rhashtable without holding the lock, if this is a problem, we can move the check to the lock, and schedule the workqueue after the lock.

Modified so that atomic_inc is also moved outside of the bucket lock along with the growth above 75% check.

Weakness

The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.

Affected Software

Extended Description

Locking is a type of synchronization behavior that ensures that multiple independently-operating processes or threads do not interfere with each other when accessing the same resource. All processes/threads are expected to follow the same steps for locking. If these steps are not followed precisely - or if no locking is done at all - then another process/thread could modify the shared resource in a way that is not visible or predictable to the original process. This can lead to data or memory corruption, denial of service, etc.

Potential Mitigations

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/25.html
• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/27.html

References

• https://git.kernel.org/stable/c/ced8ce3c83a7150c5f5d371a8c332d7bc7f9b66d
• https://git.kernel.org/stable/c/e1d3422c95f003eba241c176adfe593c33e8a8f6
• https://git.kernel.org/stable/c/eb2e58484b838fb4e777ee9721bb9e20e6ca971d