v4l2videodec: ensure pool exists before orphaning it

In commit e2ff87732d0b ("v4l2videodec: support orphaning") support for
orphaning the capture buffer pool was added when the format is
renegotiated. However, the commit forgot to check that a pool existed
before doing this. This is needed because it's possible for the format
to be renegotiated before a capture pool is allocated, which would
result in trying to orphan a NULL pool and lead to a NULL pointer
dereference.

Fix this by checking a pool exists first. If the pool doesn't exist,
there are no buffers to be reclaimed, so skip the allocation query in
that case.

diff --git a/sys/v4l2/gstv4l2videodec.c b/sys/v4l2/gstv4l2videodec.c
index d408130..39f845c 100644 (file)
--- a/sys/v4l2/gstv4l2videodec.c
+++ b/sys/v4l2/gstv4l2videodec.c
@@ -246,7 +246,8 @@ gst_v4l2_video_dec_set_format (GstVideoDecoder * decoder,
      * the complexity and should not have much impact in performance since the
      * following allocation query will happen on a drained pipeline and won't
      * block. */
-    if (!gst_v4l2_buffer_pool_orphan (&self->v4l2capture->pool)) {
+    if (self->v4l2capture->pool &&
+        !gst_v4l2_buffer_pool_orphan (&self->v4l2capture->pool)) {
       GstCaps *caps = gst_pad_get_current_caps (decoder->srcpad);
       if (caps) {
         GstQuery *query = gst_query_new_allocation (caps, FALSE);