This is a note to let you know that I've just added the patch titled usb: dwc3: gadget: delay unmap of bounced requests to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: usb-dwc3-gadget-delay-unmap-of-bounced-requests.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From de288e36fe33f7e06fa272bc8e2f85aa386d99aa Mon Sep 17 00:00:00 2001 From: Janusz Dziedzic <januszx.dziedzic@xxxxxxxxx> Date: Mon, 13 Mar 2017 14:11:32 +0200 Subject: usb: dwc3: gadget: delay unmap of bounced requests From: Janusz Dziedzic <januszx.dziedzic@xxxxxxxxx> commit de288e36fe33f7e06fa272bc8e2f85aa386d99aa upstream. In the case of bounced ep0 requests, we must delay DMA operation until after ->complete() otherwise we might overwrite contents of req->buf. This caused problems with RNDIS gadget. Signed-off-by: Janusz Dziedzic <januszx.dziedzic@xxxxxxxxx> Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/dwc3/gadget.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -174,6 +174,7 @@ void dwc3_gadget_giveback(struct dwc3_ep int status) { struct dwc3 *dwc = dep->dwc; + unsigned int unmap_after_complete = false; req->started = false; list_del(&req->list); @@ -182,11 +183,19 @@ void dwc3_gadget_giveback(struct dwc3_ep if (req->request.status == -EINPROGRESS) req->request.status = status; - if (dwc->ep0_bounced && dep->number <= 1) + /* + * NOTICE we don't want to unmap before calling ->complete() if we're + * dealing with a bounced ep0 request. If we unmap it here, we would end + * up overwritting the contents of req->buf and this could confuse the + * gadget driver. + */ + if (dwc->ep0_bounced && dep->number <= 1) { dwc->ep0_bounced = false; - - usb_gadget_unmap_request(&dwc->gadget, &req->request, - req->direction); + unmap_after_complete = true; + } else { + usb_gadget_unmap_request(&dwc->gadget, + &req->request, req->direction); + } trace_dwc3_gadget_giveback(req); @@ -194,6 +203,10 @@ void dwc3_gadget_giveback(struct dwc3_ep usb_gadget_giveback_request(&dep->endpoint, &req->request); spin_lock(&dwc->lock); + if (unmap_after_complete) + usb_gadget_unmap_request(&dwc->gadget, + &req->request, req->direction); + if (dep->number > 1) pm_runtime_put(dwc->dev); } Patches currently in stable-queue which might be from januszx.dziedzic@xxxxxxxxx are queue-4.9/usb-dwc3-gadget-delay-unmap-of-bounced-requests.patch