Hi Hans, On 2017-12-04 10:05:35 +0100, Hans Verkuil wrote: > Hi Niklas, > > On 11/16/2017 01:27 AM, Laurent Pinchart wrote: > > Hi Niklas, > > > > On Thursday, 16 November 2017 01:34:33 EET Niklas Söderlund wrote: > >> On 2017-11-16 00:49:07 +0200, Laurent Pinchart wrote: > >>> The rvin_dev data structure contains driver private data for an instance > >>> of the VIN. It is allocated dynamically at probe time, and must be freed > >>> once all users are gone. > >>> > >>> The structure is currently allocated with devm_kzalloc(), which results > >>> in memory being freed when the device is unbound. If a userspace > >>> application is currently performing an ioctl call, or just keeps the > >>> device node open and closes it later, this will lead to accessing freed > >>> memory. > >>> > >>> Fix the problem by implementing a V4L2 release handler for the video > >>> node associated with the VIN instance (called when the last user of the > >>> video node releases it), and freeing memory explicitly from the release > >>> handler. > >>> > >>> Signed-off-by: Laurent Pinchart > >>> <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx> > >> > >> Acked-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx> > >> > >> This patch is based on-top of the VIN Gen3 enablement series not yet > >> upstream. This is OK for me, just wanted to check that this was the > >> intention as to minimize conflicts between the two. > > > > Yes, that's my intention. The patch should be included, or possibly squashed > > in, your development branch. > > > > Has this patch been added in your v8 series? If not, can you add it when you > post a v9? This patch needs more work, with the video device now registered at complete() time and unregistered at unbind() time. Applying this would free the rcar-vin private data structure at unbind() which probably not what we want. I think this issue should be addressed but maybe together with a patch-set targeting the generic problem with video device lifetimes in v4l2 framework? For now I would be happy to focus on getting Gen3 support picked-up and observe what Laurent's work on lifetime issues brings and adept the rcar-vin driver to take advantage of that once it's ready. > > Thanks, > > Hans -- Regards, Niklas Söderlund
