| Message ID | 1350667166-3559-1-git-send-email-simon.haggett@realvnc.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
> -----Original Message----- > From: Felipe Balbi [mailto:balbi@ti.com] > Sent: Saturday, October 20, 2012 1:37 AM > To: Simon Haggett > Cc: Li Yang-R58472; Felipe Balbi; Greg Kroah-Hartman; linux- > usb@vger.kernel.org; linuxppc-dev@lists.ozlabs.org; linux- > kernel@vger.kernel.org; Laurent Pinchart > Subject: Re: [PATCH 1/1] usb: gadget: Don't attempt to dequeue requests > for a disabled USB endpoint on Freescale hardware > > Hi, > > On Fri, Oct 19, 2012 at 06:19:26PM +0100, Simon Haggett wrote: > > Some gadget drivers may attempt to dequeue requests for an endpoint > > that has already been disabled. For example, in the UVC gadget driver, > > uvc_function_set_alt() will call usb_ep_disable() when alt setting 0 > > is selected. When the userspace application subsequently issues the > > VIDIOC_STREAMOFF ioctl, uvc_video_enable() invokes usb_ep_dequeue() to > ensure that all requests have been cancelled. > > bug is on uvc gadget, then. Laurent ? > > Also, fsl should be removed from the tree, I'm trying to persuade iMX > folks to use drivers/usb/chipidea instead. Besides the iMX usage, the driver is also being used by many Freescale PowerPC/Coldfire SoCs. I agree that it's ideal to move to a common driver. But it is a large task to make the chipidea driver works for all the hardware that fsl_udc had supported and been tested on. > > > For the Freescale High Speed Dual-Role USB controller, > > fsl_ep_dequeue() provides the implementation of usb_ep_dequeue(). If > > this is called for a disabled endpoint, a kernel oops will occur when > the ep->ep.desc field is dereferenced (by ep_index()). > > fsl_ep_disable() sets this field to NULL, as well as deleting all > > pending requests for the endpoint. > > > > This patch adds an additional check to fsl_ep_dequeue() to ensure that > > the endpoint has not already been disabled before attempting to dequeue > requests. > > > > Signed-off-by: Simon Haggett <simon.haggett@realvnc.com> > > --- > > drivers/usb/gadget/fsl_udc_core.c | 5 ++++- > > 1 files changed, 4 insertions(+), 1 deletions(-) > > > > diff --git a/drivers/usb/gadget/fsl_udc_core.c > > b/drivers/usb/gadget/fsl_udc_core.c > > index 6ae70cb..acd513b 100644 > > --- a/drivers/usb/gadget/fsl_udc_core.c > > +++ b/drivers/usb/gadget/fsl_udc_core.c > > @@ -955,7 +955,10 @@ static int fsl_ep_dequeue(struct usb_ep *_ep, > struct usb_request *_req) > > int ep_num, stopped, ret = 0; > > u32 epctrl; > > > > - if (!_ep || !_req) > > + /* Ensure that the ep and request are valid, and the ep is not > > + * disabled > > + */ > > + if (!_ep || !_req || !ep->ep.desc) > > return -EINVAL; > > > > spin_lock_irqsave(&ep->udc->lock, flags); > > -- > > 1.7.4.1 > > > > -- > balbi
On Mon, Oct 22, 2012 at 03:33:19AM +0000, Li Yang-R58472 wrote: > > > > -----Original Message----- > > From: Felipe Balbi [mailto:balbi@ti.com] > > Sent: Saturday, October 20, 2012 1:37 AM > > To: Simon Haggett > > Cc: Li Yang-R58472; Felipe Balbi; Greg Kroah-Hartman; linux- > > usb@vger.kernel.org; linuxppc-dev@lists.ozlabs.org; linux- > > kernel@vger.kernel.org; Laurent Pinchart > > Subject: Re: [PATCH 1/1] usb: gadget: Don't attempt to dequeue requests > > for a disabled USB endpoint on Freescale hardware > > > > Hi, > > > > On Fri, Oct 19, 2012 at 06:19:26PM +0100, Simon Haggett wrote: > > > Some gadget drivers may attempt to dequeue requests for an endpoint > > > that has already been disabled. For example, in the UVC gadget driver, > > > uvc_function_set_alt() will call usb_ep_disable() when alt setting 0 > > > is selected. When the userspace application subsequently issues the > > > VIDIOC_STREAMOFF ioctl, uvc_video_enable() invokes usb_ep_dequeue() to > > ensure that all requests have been cancelled. > > > > bug is on uvc gadget, then. Laurent ? > > > > Also, fsl should be removed from the tree, I'm trying to persuade iMX > > folks to use drivers/usb/chipidea instead. > > Besides the iMX usage, the driver is also being used by many Freescale > PowerPC/Coldfire SoCs. I agree that it's ideal to move to a common > driver. But it is a large task to make the chipidea driver works for > all the hardware that fsl_udc had supported and been tested on. I understand that, but we just can't keep so many duplicated drivers in mainline. chipidea udc had at least 3 different implementations. Now it's the time to combine all of those and stick to a single driver. Just make a plan to slowly move towards chipidea in the upcoming few merge windows. I can continue to take in bugfixes for fsl_udc, but only if I see that you guys are working towards merging with chipidea driver.
Hi, On Monday 22 October 2012 03:33:19 Li Yang-R58472 wrote: > On Saturday, October 20, 2012 1:37 AM Felipe Balbi wrote: > > On Fri, Oct 19, 2012 at 06:19:26PM +0100, Simon Haggett wrote: > > > Some gadget drivers may attempt to dequeue requests for an endpoint > > > that has already been disabled. For example, in the UVC gadget driver, > > > uvc_function_set_alt() will call usb_ep_disable() when alt setting 0 > > > is selected. When the userspace application subsequently issues the > > > VIDIOC_STREAMOFF ioctl, uvc_video_enable() invokes usb_ep_dequeue() to > > > > ensure that all requests have been cancelled. > > > > bug is on uvc gadget, then. Laurent ? We've discussed this topic a couple of months before. I believe that's not a bug. http://68.183.106.108/lists/linux-usb/msg68869.html > > Also, fsl should be removed from the tree, I'm trying to persuade iMX > > folks to use drivers/usb/chipidea instead. > > Besides the iMX usage, the driver is also being used by many Freescale > PowerPC/Coldfire SoCs. I agree that it's ideal to move to a common driver. > But it is a large task to make the chipidea driver works for all the > hardware that fsl_udc had supported and been tested on. > > > > For the Freescale High Speed Dual-Role USB controller, > > > fsl_ep_dequeue() provides the implementation of usb_ep_dequeue(). If > > > this is called for a disabled endpoint, a kernel oops will occur when > > > > the ep->ep.desc field is dereferenced (by ep_index()). > > > > > fsl_ep_disable() sets this field to NULL, as well as deleting all > > > pending requests for the endpoint. > > > > > > This patch adds an additional check to fsl_ep_dequeue() to ensure that > > > the endpoint has not already been disabled before attempting to dequeue > > > > requests. > > > > > Signed-off-by: Simon Haggett <simon.haggett@realvnc.com> > > > --- > > > > > > drivers/usb/gadget/fsl_udc_core.c | 5 ++++- > > > 1 files changed, 4 insertions(+), 1 deletions(-) > > > > > > diff --git a/drivers/usb/gadget/fsl_udc_core.c > > > b/drivers/usb/gadget/fsl_udc_core.c > > > index 6ae70cb..acd513b 100644 > > > --- a/drivers/usb/gadget/fsl_udc_core.c > > > +++ b/drivers/usb/gadget/fsl_udc_core.c > > > @@ -955,7 +955,10 @@ static int fsl_ep_dequeue(struct usb_ep *_ep, > > struct usb_request *_req) > > > > > int ep_num, stopped, ret = 0; > > > u32 epctrl; > > > > > > - if (!_ep || !_req) > > > + /* Ensure that the ep and request are valid, and the ep is not > > > + * disabled > > > + */ > > > + if (!_ep || !_req || !ep->ep.desc) > > > return -EINVAL; Shouldn't that last check be done with a lock taken ? > > > spin_lock_irqsave(&ep->udc->lock, flags);
Hi, On Mon, Oct 22, 2012 at 12:47:21PM +0200, Laurent Pinchart wrote: > Hi, > > On Monday 22 October 2012 03:33:19 Li Yang-R58472 wrote: > > On Saturday, October 20, 2012 1:37 AM Felipe Balbi wrote: > > > On Fri, Oct 19, 2012 at 06:19:26PM +0100, Simon Haggett wrote: > > > > Some gadget drivers may attempt to dequeue requests for an endpoint > > > > that has already been disabled. For example, in the UVC gadget driver, > > > > uvc_function_set_alt() will call usb_ep_disable() when alt setting 0 > > > > is selected. When the userspace application subsequently issues the > > > > VIDIOC_STREAMOFF ioctl, uvc_video_enable() invokes usb_ep_dequeue() to > > > > > > ensure that all requests have been cancelled. > > > > > > bug is on uvc gadget, then. Laurent ? > > We've discussed this topic a couple of months before. I believe that's not a > bug. > > http://68.183.106.108/lists/linux-usb/msg68869.html fair enough :-) That's a different case, however. At the link above we're discussing dequeueing a request which is already being dequeued. $SUBJECT is trying to fix dequeueing of a request for an endpoint which isn't even enabled.
Hi On 22/10/12 11:47, Laurent Pinchart wrote: > Hi, > > On Monday 22 October 2012 03:33:19 Li Yang-R58472 wrote: >> On Saturday, October 20, 2012 1:37 AM Felipe Balbi wrote: >>> On Fri, Oct 19, 2012 at 06:19:26PM +0100, Simon Haggett wrote: >>>> Some gadget drivers may attempt to dequeue requests for an endpoint >>>> that has already been disabled. For example, in the UVC gadget driver, >>>> uvc_function_set_alt() will call usb_ep_disable() when alt setting 0 >>>> is selected. When the userspace application subsequently issues the >>>> VIDIOC_STREAMOFF ioctl, uvc_video_enable() invokes usb_ep_dequeue() to >>> >>> ensure that all requests have been cancelled. >>> >>> bug is on uvc gadget, then. Laurent ? > > We've discussed this topic a couple of months before. I believe that's not a > bug. > > http://68.183.106.108/lists/linux-usb/msg68869.html > >>> Also, fsl should be removed from the tree, I'm trying to persuade iMX >>> folks to use drivers/usb/chipidea instead. >> >> Besides the iMX usage, the driver is also being used by many Freescale >> PowerPC/Coldfire SoCs. I agree that it's ideal to move to a common driver. >> But it is a large task to make the chipidea driver works for all the >> hardware that fsl_udc had supported and been tested on. >> >>>> For the Freescale High Speed Dual-Role USB controller, >>>> fsl_ep_dequeue() provides the implementation of usb_ep_dequeue(). If >>>> this is called for a disabled endpoint, a kernel oops will occur when >>> >>> the ep->ep.desc field is dereferenced (by ep_index()). >>> >>>> fsl_ep_disable() sets this field to NULL, as well as deleting all >>>> pending requests for the endpoint. >>>> >>>> This patch adds an additional check to fsl_ep_dequeue() to ensure that >>>> the endpoint has not already been disabled before attempting to dequeue >>> >>> requests. >>> >>>> Signed-off-by: Simon Haggett <simon.haggett@realvnc.com> >>>> --- >>>> >>>> drivers/usb/gadget/fsl_udc_core.c | 5 ++++- >>>> 1 files changed, 4 insertions(+), 1 deletions(-) >>>> >>>> diff --git a/drivers/usb/gadget/fsl_udc_core.c >>>> b/drivers/usb/gadget/fsl_udc_core.c >>>> index 6ae70cb..acd513b 100644 >>>> --- a/drivers/usb/gadget/fsl_udc_core.c >>>> +++ b/drivers/usb/gadget/fsl_udc_core.c >>>> @@ -955,7 +955,10 @@ static int fsl_ep_dequeue(struct usb_ep *_ep, >>> struct usb_request *_req) >>> >>>> int ep_num, stopped, ret = 0; >>>> u32 epctrl; >>>> >>>> - if (!_ep || !_req) >>>> + /* Ensure that the ep and request are valid, and the ep is not >>>> + * disabled >>>> + */ >>>> + if (!_ep || !_req || !ep->ep.desc) >>>> return -EINVAL; > > Shouldn't that last check be done with a lock taken ? I had presumed a lock wasn't necessary because ep->ep.desc is only set to NULL by fsl_ep_disable() which, since it is called by usb_ep_disable(), should only be invoked when no other task is using the endpoint (according to include/linux/usb/gadget.h). Furthermore, the chipidea UDC driver does check the equivalent of this field is not NULL without taking a lock (ep_dequeue() in drivers/usb/chipidea/udc.c). However, it is possible that I'm misunderstanding something here, so apologies if I am. > >>>> spin_lock_irqsave(&ep->udc->lock, flags); > Many thanks Simon
Hi Simon, On Monday 22 October 2012 12:49:51 Simon Haggett wrote: > On 22/10/12 11:47, Laurent Pinchart wrote: > > On Monday 22 October 2012 03:33:19 Li Yang-R58472 wrote: > >> On Saturday, October 20, 2012 1:37 AM Felipe Balbi wrote: > >>> On Fri, Oct 19, 2012 at 06:19:26PM +0100, Simon Haggett wrote: > >>>> Some gadget drivers may attempt to dequeue requests for an endpoint > >>>> that has already been disabled. For example, in the UVC gadget driver, > >>>> uvc_function_set_alt() will call usb_ep_disable() when alt setting 0 > >>>> is selected. When the userspace application subsequently issues the > >>>> VIDIOC_STREAMOFF ioctl, uvc_video_enable() invokes usb_ep_dequeue() to > >>> > >>> ensure that all requests have been cancelled. > >>> > >>> bug is on uvc gadget, then. Laurent ? > > > > We've discussed this topic a couple of months before. I believe that's not > > a bug. > > > > http://68.183.106.108/lists/linux-usb/msg68869.html > > > >>> Also, fsl should be removed from the tree, I'm trying to persuade iMX > >>> folks to use drivers/usb/chipidea instead. > >> > >> Besides the iMX usage, the driver is also being used by many Freescale > >> PowerPC/Coldfire SoCs. I agree that it's ideal to move to a common > >> driver. > >> But it is a large task to make the chipidea driver works for all the > >> hardware that fsl_udc had supported and been tested on. > >> > >>>> For the Freescale High Speed Dual-Role USB controller, > >>>> fsl_ep_dequeue() provides the implementation of usb_ep_dequeue(). If > >>>> this is called for a disabled endpoint, a kernel oops will occur when > >>> > >>> the ep->ep.desc field is dereferenced (by ep_index()). > >>> > >>>> fsl_ep_disable() sets this field to NULL, as well as deleting all > >>>> pending requests for the endpoint. > >>>> > >>>> This patch adds an additional check to fsl_ep_dequeue() to ensure that > >>>> the endpoint has not already been disabled before attempting to dequeue > >>> > >>> requests. > >>> > >>>> Signed-off-by: Simon Haggett <simon.haggett@realvnc.com> > >>>> --- > >>>> > >>>> drivers/usb/gadget/fsl_udc_core.c | 5 ++++- > >>>> 1 files changed, 4 insertions(+), 1 deletions(-) > >>>> > >>>> diff --git a/drivers/usb/gadget/fsl_udc_core.c > >>>> b/drivers/usb/gadget/fsl_udc_core.c > >>>> index 6ae70cb..acd513b 100644 > >>>> --- a/drivers/usb/gadget/fsl_udc_core.c > >>>> +++ b/drivers/usb/gadget/fsl_udc_core.c > >>>> @@ -955,7 +955,10 @@ static int fsl_ep_dequeue(struct usb_ep *_ep, > >>> > >>> struct usb_request *_req) > >>> > >>>> int ep_num, stopped, ret = 0; > >>>> u32 epctrl; > >>>> > >>>> - if (!_ep || !_req) > >>>> + /* Ensure that the ep and request are valid, and the ep is not > >>>> + * disabled > >>>> + */ > >>>> + if (!_ep || !_req || !ep->ep.desc) > >>>> > >>>> return -EINVAL; > > > > Shouldn't that last check be done with a lock taken ? > > I had presumed a lock wasn't necessary because ep->ep.desc is only set > to NULL by fsl_ep_disable() which, since it is called by > usb_ep_disable(), should only be invoked when no other task is using the > endpoint (according to include/linux/usb/gadget.h). Furthermore, the > chipidea UDC driver does check the equivalent of this field is not NULL > without taking a lock (ep_dequeue() in drivers/usb/chipidea/udc.c). > > However, it is possible that I'm misunderstanding something here, so > apologies if I am. I might be wrong as well :-) I just wanted to point out something that appeared to me as a possible issue. > >>>> spin_lock_irqsave(&ep->udc->lock, flags);
Hi Felipe, On Monday 22 October 2012 13:56:01 Felipe Balbi wrote: > On Mon, Oct 22, 2012 at 12:47:21PM +0200, Laurent Pinchart wrote: > > On Monday 22 October 2012 03:33:19 Li Yang-R58472 wrote: > > > On Saturday, October 20, 2012 1:37 AM Felipe Balbi wrote: > > > > On Fri, Oct 19, 2012 at 06:19:26PM +0100, Simon Haggett wrote: > > > > > Some gadget drivers may attempt to dequeue requests for an endpoint > > > > > that has already been disabled. For example, in the UVC gadget > > > > > driver, uvc_function_set_alt() will call usb_ep_disable() when alt > > > > > setting 0 is selected. When the userspace application subsequently > > > > > issues the VIDIOC_STREAMOFF ioctl, uvc_video_enable() invokes > > > > > usb_ep_dequeue() to ensure that all requests have been cancelled. > > > > > > > > bug is on uvc gadget, then. Laurent ? > > > > We've discussed this topic a couple of months before. I believe that's not > > a bug. > > > > http://68.183.106.108/lists/linux-usb/msg68869.html > > fair enough :-) > > That's a different case, however. At the link above we're discussing > dequeueing a request which is already being dequeued. $SUBJECT is trying > to fix dequeueing of a request for an endpoint which isn't even enabled. You've got a point there :-) That's a different case indeed, I'm open to (at least evaluating) a fix in the UVC gadget driver if you think that's better.
Hi, On Thu, Oct 25, 2012 at 02:36:24AM +0200, Laurent Pinchart wrote: > Hi Felipe, > > On Monday 22 October 2012 13:56:01 Felipe Balbi wrote: > > On Mon, Oct 22, 2012 at 12:47:21PM +0200, Laurent Pinchart wrote: > > > On Monday 22 October 2012 03:33:19 Li Yang-R58472 wrote: > > > > On Saturday, October 20, 2012 1:37 AM Felipe Balbi wrote: > > > > > On Fri, Oct 19, 2012 at 06:19:26PM +0100, Simon Haggett wrote: > > > > > > Some gadget drivers may attempt to dequeue requests for an endpoint > > > > > > that has already been disabled. For example, in the UVC gadget > > > > > > driver, uvc_function_set_alt() will call usb_ep_disable() when alt > > > > > > setting 0 is selected. When the userspace application subsequently > > > > > > issues the VIDIOC_STREAMOFF ioctl, uvc_video_enable() invokes > > > > > > usb_ep_dequeue() to ensure that all requests have been cancelled. > > > > > > > > > > bug is on uvc gadget, then. Laurent ? > > > > > > We've discussed this topic a couple of months before. I believe that's not > > > a bug. > > > > > > http://68.183.106.108/lists/linux-usb/msg68869.html > > > > fair enough :-) > > > > That's a different case, however. At the link above we're discussing > > dequeueing a request which is already being dequeued. $SUBJECT is trying > > to fix dequeueing of a request for an endpoint which isn't even enabled. > > You've got a point there :-) That's a different case indeed, I'm open to (at > least evaluating) a fix in the UVC gadget driver if you think that's better. I _do_ think that's better. If the endpoint isn't even enabled, why are you trying to dequeue a request ? :-) cheers
diff --git a/drivers/usb/gadget/fsl_udc_core.c b/drivers/usb/gadget/fsl_udc_core.c index 6ae70cb..acd513b 100644 --- a/drivers/usb/gadget/fsl_udc_core.c +++ b/drivers/usb/gadget/fsl_udc_core.c @@ -955,7 +955,10 @@ static int fsl_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req) int ep_num, stopped, ret = 0; u32 epctrl; - if (!_ep || !_req) + /* Ensure that the ep and request are valid, and the ep is not + * disabled + */ + if (!_ep || !_req || !ep->ep.desc) return -EINVAL; spin_lock_irqsave(&ep->udc->lock, flags);
Some gadget drivers may attempt to dequeue requests for an endpoint that has already been disabled. For example, in the UVC gadget driver, uvc_function_set_alt() will call usb_ep_disable() when alt setting 0 is selected. When the userspace application subsequently issues the VIDIOC_STREAMOFF ioctl, uvc_video_enable() invokes usb_ep_dequeue() to ensure that all requests have been cancelled. For the Freescale High Speed Dual-Role USB controller, fsl_ep_dequeue() provides the implementation of usb_ep_dequeue(). If this is called for a disabled endpoint, a kernel oops will occur when the ep->ep.desc field is dereferenced (by ep_index()). fsl_ep_disable() sets this field to NULL, as well as deleting all pending requests for the endpoint. This patch adds an additional check to fsl_ep_dequeue() to ensure that the endpoint has not already been disabled before attempting to dequeue requests. Signed-off-by: Simon Haggett <simon.haggett@realvnc.com> --- drivers/usb/gadget/fsl_udc_core.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-)