In the Linux kernel, the following vulnerability has been resolved:
media: pwc: Return queued buffers on start_streaming() failure
The vb2 framework hands buffers to the driver via buf_queue() before
calling start_streaming(). If start_streaming() returns an error
without first returning those buffers via vb2_buffer_done(),
vb2_start_streaming() fires WARN_ON(owned_by_drv_count) and the queued
buffers leak.
pwc's start_streaming() had two early returns that hit this trap:
-ENODEV when the USB device was already disconnected, and -ERESTARTSYS
when mutex_lock_interruptible() was interrupted by a signal. Call the
existing pwc_cleanup_queued_bufs() helper with VB2_BUF_STATE_QUEUED
before returning (matching the state already used by the
pwc_isoc_init() error path in the same function).
This mirrors the uvcvideo fix in commit 4cf3b6fd54eb ("media: uvcvideo:
Return queued buffers on start_streaming() failure").