CVE-2024-56532: ALSA: us122l: Use snd_card_free_when_closed() at disconnection

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-12-27 · updated 2026-06-17
Weakness: CWE-667

Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: us122l: Use snd_card_free_when_closed() at disconnection The USB disconnect callback is supposed to be short and not too-long waiting. OTOH, the current code uses snd_card_free() at disconnection, but this waits for the close of all used fds, hence it can take long. It eventually blocks the upper layer USB ioctls, which may trigger a soft lockup. An easy workaround is to replace snd_card_free() with snd_card_free_when_closed(). This variant returns immediately while the release of resources is done asynchronously by the card device release at the last close. The loop of us122l->mmap_count check is dropped as well. The check is useless for the asynchronous operation with *_when_closed().

Affected products

Linux kernel: from 2.6.28 before 4.19.325; from 4.20 before 5.4.287; from 5.5 before 5.10.231; from 5.11 before 5.15.174; from 5.16 before 6.1.120; from 6.2 before 6.6.64 — fixed in 4.19.325, 5.10.231, 5.15.174, 5.4.287, 6.1.120, 6.11.11

How to fix

Upgrade to a fixed version: Linux kernel 4.19.325, 5.10.231, 5.15.174, 5.4.287. Check the vendor advisory for mitigations.

References

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