[PATCH] saa7134: fix thread shutdown handling

[PATCH] saa7134: fix thread shutdown handling

[Jeff Mahoney]

 This patch changes the test for the thread pid from >= 0 to > 0.

 When the saa8134 driver initialization fails after a certain point,
 it goes through the complete shutdown process for the driver. Part
 of shutting it down includes tearing down the thread for tv audio.

 The test for tearing down the thread tests for >= 0. Since the dev
 structure is kzalloc'd, the test will always be true if we haven't
 tried to start the thread yet. We end up waiting on pid 0 to complete,
 which will never happen, so we lock up.

 This bug was observed in Novell Bugzilla 284718, when request_irq()
 failed.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>

---

 drivers/media/video/saa7134/saa7134-tvaudio.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/media/video/saa7134/saa7134-tvaudio.c	2007-06-12 15:45:16.000000000 -0400
+++ b/drivers/media/video/saa7134/saa7134-tvaudio.c	2007-06-15 14:16:14.000000000 -0400
@@ -1005,7 +1005,7 @@
 int saa7134_tvaudio_fini(struct saa7134_dev *dev)
 {
 	/* shutdown tvaudio thread */
-	if (dev->thread.pid >= 0) {
+	if (dev->thread.pid > 0) {
 		dev->thread.shutdown = 1;
 		wake_up_interruptible(&dev->thread.wq);
 		wait_for_completion(&dev->thread.exit);

-- 
Jeff Mahoney
SUSE Labs

Re: [PATCH] saa7134: fix thread shutdown handling

[Andrew Morton]

> On Thu, 21 Jun 2007 14:45:22 -0400 Jeff Mahoney <jeffm@suse.com> wrote:
>  This patch changes the test for the thread pid from >= 0 to > 0.
> 
>  When the saa8134 driver initialization fails after a certain point,
>  it goes through the complete shutdown process for the driver. Part
>  of shutting it down includes tearing down the thread for tv audio.
> 
>  The test for tearing down the thread tests for >= 0. Since the dev
>  structure is kzalloc'd, the test will always be true if we haven't
>  tried to start the thread yet. We end up waiting on pid 0 to complete,
>  which will never happen, so we lock up.
> 
>  This bug was observed in Novell Bugzilla 284718, when request_irq()
>  failed.
> 
> Signed-off-by: Jeff Mahoney <jeffm@suse.com>
> 
> ---
> 
>  drivers/media/video/saa7134/saa7134-tvaudio.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> --- a/drivers/media/video/saa7134/saa7134-tvaudio.c	2007-06-12 15:45:16.000000000 -0400
> +++ b/drivers/media/video/saa7134/saa7134-tvaudio.c	2007-06-15 14:16:14.000000000 -0400
> @@ -1005,7 +1005,7 @@
>  int saa7134_tvaudio_fini(struct saa7134_dev *dev)
>  {
>  	/* shutdown tvaudio thread */
> -	if (dev->thread.pid >= 0) {
> +	if (dev->thread.pid > 0) {
>  		dev->thread.shutdown = 1;
>  		wake_up_interruptible(&dev->thread.wq);
>  		wait_for_completion(&dev->thread.exit);
> 

This is no longer applicable to the dvb devel tree, because this code has
been converted to the kthread API.

However I guess we do want this in 2.6.22 and in 2.6.21.x.  Mauro, if
that's OK, do you want me to do the merges?

Re: [PATCH] saa7134: fix thread shutdown handling

[Mauro Carvalho Chehab]

Em Sáb, 2007-06-23 às 09:54 -0700, Andrew Morton escreveu:
> > On Thu, 21 Jun 2007 14:45:22 -0400 Jeff Mahoney <jeffm@suse.com> wrote:
> >  This patch changes the test for the thread pid from >= 0 to > 0.
> > 
> >  When the saa8134 driver initialization fails after a certain point,
> >  it goes through the complete shutdown process for the driver. Part
> >  of shutting it down includes tearing down the thread for tv audio.
> > 
> >  The test for tearing down the thread tests for >= 0. Since the dev
> >  structure is kzalloc'd, the test will always be true if we haven't
> >  tried to start the thread yet. We end up waiting on pid 0 to complete,
> >  which will never happen, so we lock up.
> > 
> >  This bug was observed in Novell Bugzilla 284718, when request_irq()
> >  failed.
> > 
> > Signed-off-by: Jeff Mahoney <jeffm@suse.com>
> > 
> > ---
> > 
> >  drivers/media/video/saa7134/saa7134-tvaudio.c |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > --- a/drivers/media/video/saa7134/saa7134-tvaudio.c	2007-06-12 15:45:16.000000000 -0400
> > +++ b/drivers/media/video/saa7134/saa7134-tvaudio.c	2007-06-15 14:16:14.000000000 -0400
> > @@ -1005,7 +1005,7 @@
> >  int saa7134_tvaudio_fini(struct saa7134_dev *dev)
> >  {
> >  	/* shutdown tvaudio thread */
> > -	if (dev->thread.pid >= 0) {
> > +	if (dev->thread.pid > 0) {
> >  		dev->thread.shutdown = 1;
> >  		wake_up_interruptible(&dev->thread.wq);
> >  		wait_for_completion(&dev->thread.exit);
> > 
> 
> This is no longer applicable to the dvb devel tree, because this code has
> been converted to the kthread API.
> 
> However I guess we do want this in 2.6.22 and in 2.6.21.x.  Mauro, if
> that's OK, do you want me to do the merges?

Yes, please, Andrew. I'm OK on merging this for the -stable trees.
> 
-- 
Cheers,
Mauro