CVE-2024-38600

/// Technical description

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

ALSA: Fix deadlocks with kctl removals at disconnection

In snd_card_disconnect(), we set card->shutdown flag at the beginning,

call callbacks and do sync for card->power_ref_sleep waiters at the

end. The callback may delete a kctl element, and this can lead to a

deadlock when the device was in the suspended state. Namely:

* A process waits for the power up at snd_power_ref_and_wait() in

snd_ctl_info() or read/write() inside card->controls_rwsem.

* The system gets disconnected meanwhile, and the driver tries to

delete a kctl via snd_ctl_remove*(); it tries to take

card->controls_rwsem again, but this is already locked by the

above. Since the sleeper isn't woken up, this deadlocks.

An easy fix is to wake up sleepers before processing the driver

disconnect callbacks but right after setting the card->shutdown flag.

Then all sleepers will abort immediately, and the code flows again.

So, basically this patch

/// 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