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

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

[Alexander Strakh]

        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

Сhecks the return code of pd_vidioc_s_fm before mutex_unlocking.

Signed-off-by: Alexander Strakh <strakh@ispras.ru>

---
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;
 }
 

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

[Huang Shijie]

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@ispras.ru>:
>        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
>
> Сhecks the return code of pd_vidioc_s_fm before mutex_unlocking.
>
> Signed-off-by: Alexander Strakh <strakh@ispras.ru>
>
> ---
> 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;
>  }
>
>
>

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

[Mauro Carvalho Chehab]

Em 13-12-2010 13:59, iceberg escreveu:
> 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
> 
> ?hecks the return code of pd_vidioc_s_fm before mutex_unlocking.
> 
> Signed-off-by: Alexander Strakh <strakh@ispras.ru>
> 
> ---
> --
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> 
> 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;
>  }
> 

Thanks for the patch, but the better is to keep the calls to mutex_lock/mutex_unlock
at the same function. So, instead of adding an "if" at vidioc_s_fmt, please remove
the mutex_unlock() from pd_vidioc_s_fmt().

Cheers,
Mauro