| Message ID | 20220616030915.149238-1-w36195@motorola.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | usb: gadget: uvc: fix list double add in uvcg_video_pump | expand |
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> > }
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
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++; }
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(+)