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SubjectRe: A reliable kernel panic (3.6.2) and system crash when visiting a particular website
At Wed, 7 Nov 2012 15:37:17 -0500 (EST),
Alan Stern wrote:
>
> On Wed, 7 Nov 2012, Takashi Iwai wrote:
>
> > > What is the right solution for this problem?
> >
> > How about the patch below? (It's for 3.6, and won't be applied cleanly
> > to 3.7, but easy to adapt.)
>
> I simplified your patch a little.

You can't drop the check of stopping endpoint. As Daniel pointed,
endpoints might be still running when it's called. I already did a
similar failure in the past, so this patch is a revised version with
the check for pending operations.

> This is for 3.7, not 3.6. I
> verified that it does fix the problem raised by the test program.
>
> If you think this is okay, I'll submit it officially.

Don't worry, my patch is also based on 3.7, too :) 3.6 patch was
provided just for convenience, testers seemed to have 3.6 systems.


thanks,

Takashi

>
> Alan Stern
>
>
>
> Index: usb-3.7/sound/usb/endpoint.h
> ===================================================================
> --- usb-3.7.orig/sound/usb/endpoint.h
> +++ usb-3.7/sound/usb/endpoint.h
> @@ -19,6 +19,7 @@ int snd_usb_endpoint_set_params(struct s
> int snd_usb_endpoint_start(struct snd_usb_endpoint *ep, int can_sleep);
> void snd_usb_endpoint_stop(struct snd_usb_endpoint *ep,
> int force, int can_sleep, int wait);
> +void snd_usb_endpoint_sync_stop(struct snd_usb_endpoint *ep);
> int snd_usb_endpoint_activate(struct snd_usb_endpoint *ep);
> int snd_usb_endpoint_deactivate(struct snd_usb_endpoint *ep);
> void snd_usb_endpoint_free(struct list_head *head);
> Index: usb-3.7/sound/usb/pcm.c
> ===================================================================
> --- usb-3.7.orig/sound/usb/pcm.c
> +++ usb-3.7/sound/usb/pcm.c
> @@ -576,6 +576,11 @@ static int snd_usb_pcm_prepare(struct sn
> subs->need_setup_ep = false;
> }
>
> + if (subs->sync_endpoint)
> + snd_usb_endpoint_sync_stop(subs->sync_endpoint);
> + if (subs->data_endpoint)
> + snd_usb_endpoint_sync_stop(subs->data_endpoint);
> +
> /* some unit conversions in runtime */
> subs->data_endpoint->maxframesize =
> bytes_to_frames(runtime, subs->data_endpoint->maxpacksize);
> Index: usb-3.7/sound/usb/endpoint.c
> ===================================================================
> --- usb-3.7.orig/sound/usb/endpoint.c
> +++ usb-3.7/sound/usb/endpoint.c
> @@ -481,7 +481,7 @@ __exit_unlock:
> /*
> * wait until all urbs are processed.
> */
> -static int wait_clear_urbs(struct snd_usb_endpoint *ep)
> +void snd_usb_endpoint_sync_stop(struct snd_usb_endpoint *ep)
> {
> unsigned long end_time = jiffies + msecs_to_jiffies(1000);
> unsigned int i;
> @@ -502,8 +502,6 @@ static int wait_clear_urbs(struct snd_us
> if (alive)
> snd_printk(KERN_ERR "timeout: still %d active urbs on EP #%x\n",
> alive, ep->ep_num);
> -
> - return 0;
> }
>
> /*
> @@ -556,7 +554,7 @@ static void release_urbs(struct snd_usb_
>
> /* stop urbs */
> deactivate_urbs(ep, force, 1);
> - wait_clear_urbs(ep);
> + snd_usb_endpoint_sync_stop(ep);
>
> for (i = 0; i < ep->nurbs; i++)
> release_urb_ctx(&ep->urb[i]);
> @@ -833,7 +831,7 @@ int snd_usb_endpoint_start(struct snd_us
> /* just to be sure */
> deactivate_urbs(ep, 0, can_sleep);
> if (can_sleep)
> - wait_clear_urbs(ep);
> + snd_usb_endpoint_sync_stop(ep);
>
> ep->active_mask = 0;
> ep->unlink_mask = 0;
> @@ -917,7 +915,7 @@ void snd_usb_endpoint_stop(struct snd_us
> ep->prepare_data_urb = NULL;
>
> if (wait)
> - wait_clear_urbs(ep);
> + snd_usb_endpoint_sync_stop(ep);
> }
> }
>
> @@ -940,7 +938,7 @@ int snd_usb_endpoint_deactivate(struct s
> return -EINVAL;
>
> deactivate_urbs(ep, 1, 1);
> - wait_clear_urbs(ep);
> + snd_usb_endpoint_sync_stop(ep);
>
> if (ep->use_count != 0)
> return 0;
>


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