On Thu, Nov 15, 2018 at 11:29:35AM +0100, Hans Verkuil wrote: > On 11/14/18 20:59, Laurent Pinchart wrote: > > Hi Philipp, > > > > Thank you for the patch. > > > > On Wednesday, 14 November 2018 17:04:49 EET Philipp Zabel wrote: > >> From: John Sheu <sheu@xxxxxxxxxxxx> > >> > >> Videobuf2 presently does not allow VIDIOC_REQBUFS to destroy outstanding > >> buffers if the queue is of type V4L2_MEMORY_MMAP, and if the buffers are > >> considered "in use". This is different behavior than for other memory > >> types and prevents us from deallocating buffers in following two cases: > >> > >> 1) There are outstanding mmap()ed views on the buffer. However even if > >> we put the buffer in reqbufs(0), there will be remaining references, > >> due to vma .open/close() adjusting vb2 buffer refcount appropriately. > >> This means that the buffer will be in fact freed only when the last > >> mmap()ed view is unmapped. > > > > While I agree that we should remove this restriction, it has helped me in the > > past to find missing munmap() in userspace. This patch thus has the potential > > of causing memory leaks in userspace. Is there a way we could assist > > application developers with this ? > > Should we just keep the debug message? (rephrased of course) > > That way you can enable debugging and see that this happens. > > It sounds reasonable to me. Makes sense IMO. -- Sakari Ailus e-mail: sakari.ailus@xxxxxx
