Re: [PATCH 1/4] drm/msm: fix memleak on release

[Daniel Vetter]

On Tue, Nov 12, 2019 at 11:40:01AM +0100, Johan Hovold wrote:
> On Wed, Oct 30, 2019 at 11:01:46AM +0100, Johan Hovold wrote:
> > On Thu, Oct 10, 2019 at 03:13:30PM +0200, Johan Hovold wrote:
> > > If a process is interrupted while accessing the "gpu" debugfs file and
> > > the drm device struct_mutex is contended, release() could return early
> > > and fail to free related resources.
> > > 
> > > Note that the return value from release() is ignored.
> > > 
> > > Fixes: 4f776f4511c7 ("drm/msm/gpu: Convert the GPU show function to use the GPU state")
> > > Cc: stable <stable@xxxxxxxxxxxxxxx>     # 4.18
> > > Cc: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>
> > > Cc: Rob Clark <robdclark@xxxxxxxxx>
> > > Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
> > > ---
> > 
> > Rob, Sean,
> > 
> > Sending a reminder about this one, which is not yet in linux-next.
> > 
> > Perhaps Daniel can pick it up otherwise?
> 
> Another two weeks, another reminder. This one is still not in -next.

Well msm is maintained in a separate tree, so the usual group maintainer
fallback for when patches are stuck doesn't apply.

Rob, Sean, time to reconsider drm-misc for msm? I think there's some more
oddball patches that occasionally get stuck for msm ...

Also +Dave.
-Daniel

> 
> Johan
> 
> > >  drivers/gpu/drm/msm/msm_debugfs.c | 6 +-----
> > >  1 file changed, 1 insertion(+), 5 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/msm/msm_debugfs.c b/drivers/gpu/drm/msm/msm_debugfs.c
> > > index 6be879578140..1c74381a4fc9 100644
> > > --- a/drivers/gpu/drm/msm/msm_debugfs.c
> > > +++ b/drivers/gpu/drm/msm/msm_debugfs.c
> > > @@ -47,12 +47,8 @@ static int msm_gpu_release(struct inode *inode, struct file *file)
> > >  	struct msm_gpu_show_priv *show_priv = m->private;
> > >  	struct msm_drm_private *priv = show_priv->dev->dev_private;
> > >  	struct msm_gpu *gpu = priv->gpu;
> > > -	int ret;
> > > -
> > > -	ret = mutex_lock_interruptible(&show_priv->dev->struct_mutex);
> > > -	if (ret)
> > > -		return ret;
> > >  
> > > +	mutex_lock(&show_priv->dev->struct_mutex);
> > >  	gpu->funcs->gpu_state_put(show_priv->state);
> > >  	mutex_unlock(&show_priv->dev->struct_mutex);

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch