CVE-2026-53242ALSA: PCM: Fix wait queue list corruption in snd_pcm_drain() on linked streams

Official description

In the Linux kernel, the following vulnerability has been resolved: ALSA: PCM: Fix wait queue list corruption in snd_pcm_drain() on linked streams snd_pcm_drain() uses init_waitqueue_entry which does not clear entry.prev/next, and add_wait_queue with a conditional remove_wait_queue that is skipped when to_check is no longer in the group after concurrent UNLINK. The orphaned wait entry remains on the unlinked substream sleep queue. On the next drain iteration, add_wait_queue adds the entry to a new queue while still linked on the old one, corrupting both lists. A subsequent wake_up dereferences NULL at the func pointer (mapped from the spinlock at offset 0 of the misinterpreted wait_queue_head_t), causing a kernel panic. Replace init_waitqueue_entry/add_wait_queue/conditional remove_wait_queue with init_wait_entry/prepare_to_wait/ finish_wait. init_wait_entry clears prev/next via INIT_LIST_HEAD on each iteration and sets autoremove_wake_function which auto-removes the entry on wake-up. finish_wait safely handles both the already-removed and still-queued cases.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/cac5bf3500ee6422cf64e0df0b5daeecfed42917
• https://git.kernel.org/stable/c/06eca2235a3fd281dddf25b0a97772b25b5bb573
• https://git.kernel.org/stable/c/d842f26a167e77a36f3ed333b9fa99d36ef99fe6
• https://git.kernel.org/stable/c/d68b621bb5a48051932f1017a6e1bc9b18f854d0
• https://git.kernel.org/stable/c/b053fcd8912f06c30f932f5b8ec41c72de474695
• https://git.kernel.org/stable/c/cd98837db15f323463b8df07282ac723bd5c3fed
• https://git.kernel.org/stable/c/7c71a9522555ff137a9ca36b15d759ca04d84788
• https://git.kernel.org/stable/c/88fe2e3658726cb21ff2dcf9770bf672f9b9d31b
• https://cert-portal.siemens.com/productcert/html/ssa-784472.html