RE: [PATCH] staging/easycap: fix mismatch in easycap_poll() mutexlock-unlock

[Winkler, Tomas]

> -----Original Message-----
> From: Alexey Khoroshilov [mailto:khoroshilov@xxxxxxxxx]
> Sent: Monday, August 29, 2011 8:47 PM
> To: Greg Kroah-Hartman
> Cc: Alexey Khoroshilov; Winkler, Tomas; Mike Thomas;
> devel@xxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; ldv-
> project@xxxxxxxxx
> Subject: [PATCH] staging/easycap: fix mismatch in easycap_poll() mutex lock-
> unlock
> 
> In case if condition (kd != isdongle(peasycap)) becomes true,
> easycap_poll() returns without releasing
> easycapdc60_dongle[kd].mutex_video.
> The patch adds mutex_unlock() before that return.
> 
> Found by Linux Driver Verification project (linuxtesting.org).
> 
> Signed-off-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>


Looks correct, thanks
Tomas

> ---
>  drivers/staging/easycap/easycap_main.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/staging/easycap/easycap_main.c
> b/drivers/staging/easycap/easycap_main.c
> index bea2816..3ea51c3 100644
> --- a/drivers/staging/easycap/easycap_main.c
> +++ b/drivers/staging/easycap/easycap_main.c
> @@ -953,8 +953,10 @@ static unsigned int easycap_poll(struct file *file,
> poll_table *wait)
>  	 *  peasycap, IN WHICH CASE A REPEAT CALL TO isdongle() WILL FAIL.
>  	 *  IF NECESSARY, BAIL OUT.
>  	 */
> -		if (kd != isdongle(peasycap))
> +		if (kd != isdongle(peasycap)) {
> +
> 	mutex_unlock(&easycapdc60_dongle[kd].mutex_video);
>  			return -ERESTARTSYS;
> +		}
>  		if (!file) {
>  			SAY("ERROR:  file is NULL\n");
> 
> 	mutex_unlock(&easycapdc60_dongle[kd].mutex_video);
> --
> 1.7.4.1

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