Re: [PATCH] media: imx: imx-mipi-csis: Fix null pointer dereference when link is not set

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Wed, Oct 11, 2023 at 08:19:03PM +0000, Sakari Ailus wrote:
> On Wed, Oct 11, 2023 at 11:06:15PM +0300, Laurent Pinchart wrote:
> > On Wed, Oct 11, 2023 at 08:01:50PM +0000, Sakari Ailus wrote:
> > > On Wed, Oct 11, 2023 at 10:48:33PM +0300, Laurent Pinchart wrote:
> > > > On Wed, Oct 11, 2023 at 07:44:59PM +0000, Sakari Ailus wrote:
> > > > > On Fri, Oct 06, 2023 at 10:46:54AM +0300, Alexander Shiyan wrote:
> > > > > > Let's add a check for src_sd before using it.
> > > > > > The link may not be set, in which case the call to this function will fail.
> > > > > 
> > > > > That would seem like an understatement.
> > > > > 
> > > > > Any idea when this was introduced (and which patch did), Fixes: and Cc:
> > > > > stable should be added if this is already in a release.
> > > > 
> > > > It's actually an issue in the pipeline validation code in the V4L2 core.
> > > > The link is marked as MUST_CONNECT, but that isn't handled properly :-(
> > > > It's been on my todo list for a while but I haven't had time to get to
> > > > it. Feel free to give it a go.
> > > 
> > > What's wrong there? It used to work at least...
> > 
> > It's called a regression :-) If I recall correctly, if the pad is not
> > connected, it's not added to the list of pads to check, and the
> > MUST_CONNECT flag is not checked.
> 
> This has potential for other similar issues in a number of drivers.

Indeed, which is why it should be fixed there.

> I suppose this broke with the graph traversal changes ~ a year ago?

I assume so, yes.

-- 
Regards,

Laurent Pinchart