Fwd: Re: BUG: double mutex_unlock in drivers/media/video/tlg2300/pd-video.c

[Alexander Strakh]

> --- Begin Message ---
> Hello,
>
> > Hi Strakh:
> > 
> > Thanks for your patch.
> > 
> > But I prefer to remove the mutex_unlock() in the pd_vidioc_s_fmt(),
> > since the pd_vidioc_s_fmt() is also called in restore_v4l2_context().
> > 
> > would you please change the patch?
> > I will ack it.
> > 
> > Best Regards
> > Huang Shijie
> > 
> > 2010/12/13 Alexander Strakh <strakh@xxxxxxxxx>:
> > >        KERNEL_VERSION: 2.6.36
> > >        SUBJECT: double mutex_lock in
> > > drivers/media/video/tlg2300/pd-video.c in function vidioc_s_fmt
> > >        SUBSCRIBE:
> > >        First mutex_unlock in function pd_vidioc_s_fmt in line 767:
> > > 
> > >  764        ret |= send_set_req(pd, VIDEO_ROSOLU_SEL,
> > >  765                                vid_resol, &cmd_status);
> > >  766        if (ret || cmd_status) {
> > >  767                mutex_unlock(&pd->lock);
> > >  768                return -EBUSY;
> > >  769        }
> > > 
> > >        Second mutex_unlock in function vidioc_s_fmt in line 806:
> > > 
> > >  805        pd_vidioc_s_fmt(pd, &f->fmt.pix);
> > >  806        mutex_unlock(&pd->lock);
> > > 
> > > Found by Linux Device Drivers Verification Project
> > > 
> > > Ðhecks the return code of pd_vidioc_s_fm before mutex_unlocking.
> > > 
> > > Signed-off-by: Alexander Strakh <strakh@xxxxxxxxx>
> > > 
> > > ---
> > > diff --git a/drivers/media/video/tlg2300/pd-video.c
> > > b/drivers/media/video/tlg2300/pd-video.c
> > > index a1ffe18..fe6bd2b 100644
> > > --- a/drivers/media/video/tlg2300/pd-video.c
> > > +++ b/drivers/media/video/tlg2300/pd-video.c
> > > @@ -802,8 +802,8 @@ static int vidioc_s_fmt(struct file *file, void *fh,
> > > struct v4l2_format *f)
> > >                return -EINVAL;
> > >        }
> > > 
> > > -       pd_vidioc_s_fmt(pd, &f->fmt.pix);
> > > -       mutex_unlock(&pd->lock);
> > > +       if(!pd_vidioc_s_fmt(pd, &f->fmt.pix))
> > > +               mutex_unlock(&pd->lock);
> > >        return 0;
> > >  }
>
>  Removing mutex_unlock from pd_vidioc_s_fmt().
>
> ---
> diff --git a/drivers/media/video/tlg2300/pd-video.c 
> b/drivers/media/video/tlg2300/pd-video.c
> index a1ffe18..6eb4538 100644
> --- a/drivers/media/video/tlg2300/pd-video.c
> +++ b/drivers/media/video/tlg2300/pd-video.c
> @@ -763,10 +763,8 @@ static int pd_vidioc_s_fmt(struct poseidon *pd, struct 
> v4l2_pix_format *pix)
>  	}
>  	ret |= send_set_req(pd, VIDEO_ROSOLU_SEL,
>  				vid_resol, &cmd_status);
> -	if (ret || cmd_status) {
> -		mutex_unlock(&pd->lock);
> +	if (ret || cmd_status)
>  		return -EBUSY;
> -	}
>  
>  	pix_def->pixelformat = pix->pixelformat; /* save it */
>  	pix->height = (context->tvnormid & V4L2_STD_525_60) ?  480 : 576;
>
>
> --- End Message ---