published December 24, 2025
In the Linux kernel, the following vulnerability has been resolved:
ALSA: pcm: Fix potential data race at PCM memory allocation helpers
The PCM memory allocation helpers have a sanity check against too many
buffer allocations. However, the check is performed without a proper
lock and the allocation isn't serialized; this allows user to allocate
more memories than predefined max size.
Practically seen, this isn't really a big problem, as it's more or
less some "soft limit" as a sanity check, and it's not possible to
allocate unlimitedly. But it's still better to address this for more
consistent behavior.
The patch covers the size check in do_alloc_pages() with the
card->memory_mutex, and increases the allocated size there for
preventing the further overflow. When the actual allocation fails,
the size is decreased accordingly.