* [PATCH] usb: gadget: uvc: fix list double add in uvcg_video_pump
@ 2022-06-16 3:09 Dan Vacura
2022-06-17 12:51 ` Laurent Pinchart
0 siblings, 1 reply; 3+ messages in thread
From: Dan Vacura @ 2022-06-16 3:09 UTC (permalink / raw)
To: linux-usb
Cc: Dan Vacura, stable, Laurent Pinchart, Felipe Balbi,
Greg Kroah-Hartman, Paul Elder, Michael Grzeschik, linux-kernel
A panic can occur if the endpoint becomes disabled and the
uvcg_video_pump adds the request back to the req_free list after it has
already been queued to the endpoint. The endpoint complete will add the
request back to the req_free list. Invalidate the local request handle
once it's been queued.
<6>[ 246.796704][T13726] configfs-gadget gadget: uvc: uvc_function_set_alt(1, 0)
<3>[ 246.797078][ T26] list_add double add: new=ffffff878bee5c40, prev=ffffff878bee5c40, next=ffffff878b0f0a90.
<6>[ 246.797213][ T26] ------------[ cut here ]------------
<2>[ 246.797224][ T26] kernel BUG at lib/list_debug.c:31!
<6>[ 246.807073][ T26] Call trace:
<6>[ 246.807180][ T26] uvcg_video_pump+0x364/0x38c
<6>[ 246.807366][ T26] process_one_work+0x2a4/0x544
<6>[ 246.807394][ T26] worker_thread+0x350/0x784
<6>[ 246.807442][ T26] kthread+0x2ac/0x320
Fixes: f9897ec0f6d3 ("usb: gadget: uvc: only pump video data if necessary")
Cc: stable@vger.kernel.org
Signed-off-by: Dan Vacura <w36195@motorola.com>
---
drivers/usb/gadget/function/uvc_video.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
index 93f42c7f800d..59e2f51b53a5 100644
--- a/drivers/usb/gadget/function/uvc_video.c
+++ b/drivers/usb/gadget/function/uvc_video.c
@@ -427,6 +427,9 @@ static void uvcg_video_pump(struct work_struct *work)
if (ret < 0) {
uvcg_queue_cancel(queue, 0);
break;
+ } else {
+ /* Endpoint now owns the request */
+ req = NULL;
}
video->req_int_count++;
}
--
2.34.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] usb: gadget: uvc: fix list double add in uvcg_video_pump
2022-06-16 3:09 [PATCH] usb: gadget: uvc: fix list double add in uvcg_video_pump Dan Vacura
@ 2022-06-17 12:51 ` Laurent Pinchart
2022-06-17 16:27 ` Dan Vacura
0 siblings, 1 reply; 3+ messages in thread
From: Laurent Pinchart @ 2022-06-17 12:51 UTC (permalink / raw)
To: Dan Vacura
Cc: linux-usb, stable, Felipe Balbi, Greg Kroah-Hartman, Paul Elder,
Michael Grzeschik, linux-kernel
Hi Dan,
Thank you for the patch.
On Wed, Jun 15, 2022 at 10:09:15PM -0500, Dan Vacura wrote:
> A panic can occur if the endpoint becomes disabled and the
> uvcg_video_pump adds the request back to the req_free list after it has
> already been queued to the endpoint. The endpoint complete will add the
> request back to the req_free list. Invalidate the local request handle
> once it's been queued.
Good catch !
> <6>[ 246.796704][T13726] configfs-gadget gadget: uvc: uvc_function_set_alt(1, 0)
> <3>[ 246.797078][ T26] list_add double add: new=ffffff878bee5c40, prev=ffffff878bee5c40, next=ffffff878b0f0a90.
> <6>[ 246.797213][ T26] ------------[ cut here ]------------
> <2>[ 246.797224][ T26] kernel BUG at lib/list_debug.c:31!
> <6>[ 246.807073][ T26] Call trace:
> <6>[ 246.807180][ T26] uvcg_video_pump+0x364/0x38c
> <6>[ 246.807366][ T26] process_one_work+0x2a4/0x544
> <6>[ 246.807394][ T26] worker_thread+0x350/0x784
> <6>[ 246.807442][ T26] kthread+0x2ac/0x320
>
> Fixes: f9897ec0f6d3 ("usb: gadget: uvc: only pump video data if necessary")
> Cc: stable@vger.kernel.org
> Signed-off-by: Dan Vacura <w36195@motorola.com>
> ---
> drivers/usb/gadget/function/uvc_video.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
> index 93f42c7f800d..59e2f51b53a5 100644
> --- a/drivers/usb/gadget/function/uvc_video.c
> +++ b/drivers/usb/gadget/function/uvc_video.c
> @@ -427,6 +427,9 @@ static void uvcg_video_pump(struct work_struct *work)
> if (ret < 0) {
> uvcg_queue_cancel(queue, 0);
> break;
> + } else {
> + /* Endpoint now owns the request */
> + req = NULL;
> }
> video->req_int_count++;
I'd write it as
if (ret < 0) {
uvcg_queue_cancel(queue, 0);
break;
}
/* Endpoint now owns the request. */
req = NULL;
video->req_int_count++;
Apart from that,
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> }
--
Regards,
Laurent Pinchart
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] usb: gadget: uvc: fix list double add in uvcg_video_pump
2022-06-17 12:51 ` Laurent Pinchart
@ 2022-06-17 16:27 ` Dan Vacura
0 siblings, 0 replies; 3+ messages in thread
From: Dan Vacura @ 2022-06-17 16:27 UTC (permalink / raw)
To: Laurent Pinchart
Cc: linux-usb, stable, Felipe Balbi, Greg Kroah-Hartman, Paul Elder,
Michael Grzeschik, linux-kernel
Hi Laurent,
Thanks for the review!
On Fri, Jun 17, 2022 at 03:51:08PM +0300, Laurent Pinchart wrote:
> Hi Dan,
>
> Thank you for the patch.
>
> On Wed, Jun 15, 2022 at 10:09:15PM -0500, Dan Vacura wrote:
> > A panic can occur if the endpoint becomes disabled and the
> > uvcg_video_pump adds the request back to the req_free list after it has
> > already been queued to the endpoint. The endpoint complete will add the
> > request back to the req_free list. Invalidate the local request handle
> > once it's been queued.
>
> Good catch !
>
> > <6>[ 246.796704][T13726] configfs-gadget gadget: uvc: uvc_function_set_alt(1, 0)
> > <3>[ 246.797078][ T26] list_add double add: new=ffffff878bee5c40, prev=ffffff878bee5c40, next=ffffff878b0f0a90.
> > <6>[ 246.797213][ T26] ------------[ cut here ]------------
> > <2>[ 246.797224][ T26] kernel BUG at lib/list_debug.c:31!
> > <6>[ 246.807073][ T26] Call trace:
> > <6>[ 246.807180][ T26] uvcg_video_pump+0x364/0x38c
> > <6>[ 246.807366][ T26] process_one_work+0x2a4/0x544
> > <6>[ 246.807394][ T26] worker_thread+0x350/0x784
> > <6>[ 246.807442][ T26] kthread+0x2ac/0x320
> >
> > Fixes: f9897ec0f6d3 ("usb: gadget: uvc: only pump video data if necessary")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Dan Vacura <w36195@motorola.com>
> > ---
> > drivers/usb/gadget/function/uvc_video.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c
> > index 93f42c7f800d..59e2f51b53a5 100644
> > --- a/drivers/usb/gadget/function/uvc_video.c
> > +++ b/drivers/usb/gadget/function/uvc_video.c
> > @@ -427,6 +427,9 @@ static void uvcg_video_pump(struct work_struct *work)
> > if (ret < 0) {
> > uvcg_queue_cancel(queue, 0);
> > break;
> > + } else {
> > + /* Endpoint now owns the request */
> > + req = NULL;
> > }
> > video->req_int_count++;
>
> I'd write it as
>
> if (ret < 0) {
> uvcg_queue_cancel(queue, 0);
> break;
> }
>
> /* Endpoint now owns the request. */
> req = NULL;
> video->req_int_count++;
This is cleaner. I'll send a v2 with this suggestion.
>
> Apart from that,
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>
> > }
>
> --
> Regards,
>
> Laurent Pinchart
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-06-16 3:09 [PATCH] usb: gadget: uvc: fix list double add in uvcg_video_pump Dan Vacura
2022-06-17 12:51 ` Laurent Pinchart
2022-06-17 16:27 ` Dan Vacura
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