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

ALSA: pcm: Fix races among concurrent hw_params and hw_free calls

Currently we have neither proper check nor protection against the
concurrent calls of PCM hw_params and hw_free ioctls, which may result
in a UAF.  Since the existing PCM stream lock can't be used for
protecting the whole ioctl operations, we need a new mutex to protect
those racy calls.

This patch introduced a new mutex, runtime->buffer_mutex, and applies
it to both hw_params and hw_free ioctl code paths.  Along with it, the
both functions are slightly modified (the mmap_count check is moved
into the state-check block) for code simplicity.

https://git.kernel.org/stable/c/0090c13cbbdffd7da079ac56f80373a9a1be0bf8

https://git.kernel.org/stable/c/0f6947f5f5208f6ebd4d76a82a4757e2839a23f8

https://git.kernel.org/stable/c/1bbf82d9f961414d6c76a08f7f843ea068e0ab7b

https://git.kernel.org/stable/c/33061d0fba51d2bf70a2ef9645f703c33fe8e438

https://git.kernel.org/stable/c/92ee3c60ec9fe64404dc035e7c41277d74aa26cb

https://git.kernel.org/stable/c/9cb6c40a6ebe4a0cfc9d6a181958211682cffea9

https://git.kernel.org/stable/c/a42aa926843acca96c0dfbde2e835b8137f2f092

https://git.kernel.org/stable/c/fbeb492694ce0441053de57699e1e2b7bc148a69