libcamera: v4l2_videodevice: Handle unexpected buffers

A kernel bug can lead to unexpected buffers being dequeued where we
haven't entered the buffer in our queuedBuffers_ list.

This causes invalid accesses if not handled correctly within libcamera,
and while it is a kernel issue, we can protect against unpatched
kernels to provide a more suitable error message.

This is fixed in the kernel by commit c592b46907ad ("media:
videobuf2-core: dequeue if start_streaming fails") [0]

[0] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c592b46907ad

Handle unexpected buffers by returning a nullptr, and move cache
management after the validation of the buffer.

Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

0 files changed, 0 insertions, 0 deletions