Hi,
good catch! Thanks.
Acked-by: Tobias Lorenz <tobias.lorenz@xxxxxxx>
Bye,
Toby
On Sun, 23 Jan 2011 12:16:54 +0300, Alexander Strakh <cromlehg@xxxxxxxxx>
wrote:
> From: Alexander Strakh <cromlehg@xxxxxxxxx>
>
>
> 1. First mutex_lock on &radio->lock in line 441
> 2. Second in line 462
>
> I think that mutex in line 462 is not needed. In kernel v2.6.36.3
function
> si470
> x_rds_on contains mutex_lock/mutex_unlock. Have no mutex_lock in line
441.
> In kernel v2.6.37 mutex_lock/mutex_unlock has been moved from
si470x_rds_on
> to fops_read. But old mutex_lock (line 462) forgot to remove.
>
> 433static ssize_t si470x_fops_read(struct file *file, char __user *buf,
> 434 size_t count, loff_t *ppos)
> 435{
> ....
> 441 mutex_lock(&radio->lock);
> 442 if ((radio->registers[SYSCONFIG1] & SYSCONFIG1_RDS) == 0)
> 443 si470x_rds_on(radio);
> 444
> 445 /* block if no new data available */
> 446 while (radio->wr_index == radio->rd_index) {
> 447 if (file->f_flags & O_NONBLOCK) {
> 448 retval = -EWOULDBLOCK;
> 449 goto done;
> 450 }
> 451 if (wait_event_interruptible(radio->read_queue,
> 452 radio->wr_index != radio->rd_index) < 0) {
> 453 retval = -EINTR;
> 454 goto done;
> 455 }
> 456 }
> 457
> 458 /* calculate block count from byte count */
> 459 count /= 3;
> 460
> 461 /* copy RDS block out of internal buffer and to user buffer
*/
> 462 mutex_lock(&radio->lock);
>
> Found by Linux Device Drivers Verification Project
>
> Remove second mutex_lock from fops_read
>
> Signed-off-by: Alexander Strakh <strakh@xxxxxxxxx>
> ---
> drivers/media/radio/si470x/radio-si470x-common.c | 1 -
> 1 files changed, 0 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/media/radio/si470x/radio-si470x-common.c
> b/drivers/media/radio/si470x/radio-si470x-common.c
> index 60c176f..38ae6cd 100644
> --- a/drivers/media/radio/si470x/radio-si470x-common.c
> +++ b/drivers/media/radio/si470x/radio-si470x-common.c
> @@ -460,7 +460,6 @@ static ssize_t si470x_fops_read(struct file *file,
> char __user *buf,
> count /= 3;
>
> /* copy RDS block out of internal buffer and to user buffer */
> - mutex_lock(&radio->lock);
> while (block_count < count) {
> if (radio->rd_index == radio->wr_index)
> break;
--
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