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usb: dwc3: gadget: fix for possible endpoint disable race 

when we call dwc3_gadget_giveback(), we end up
releasing our controller's lock. Another thread
could get scheduled and disable the endpoint,
subsequently setting dep->endpoint.desc to NULL.

In that case, we would end up dereferencing a NULL
pointer which would result in a Kernel Oops. Let's
avoid the problem by simply returning early if we
have a NULL descriptor.

Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
This commit is contained in:
Felipe Balbi 2016-05-18 12:37:21 +03:00
parent 9cad39fe4e
commit 4cb4221764
1 changed files with 17 additions and 1 deletions
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18
drivers/usb/dwc3/gadget.c
View File

@ -2041,6 +2041,14 @@ static int dwc3_cleanup_done_reqs(struct dwc3 *dwc, struct dwc3_ep *dep,
break;
} while (1);
/*
* Our endpoint might get disabled by another thread during
* dwc3_gadget_giveback(). If that happens, we're just gonna return 1
* early on so DWC3_EP_BUSY flag gets cleared
*/
if (!dep->endpoint.desc)
return 1;
if (usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
list_empty(&dep->started_list)) {
if (list_empty(&dep->pending_list)) {
@ -2078,7 +2086,7 @@ static void dwc3_endpoint_transfer_complete(struct dwc3 *dwc,
status = -ECONNRESET;
clean_busy = dwc3_cleanup_done_reqs(dwc, dep, event, status);
if (clean_busy && (is_xfer_complete ||
if (clean_busy && (!dep->endpoint.desc || is_xfer_complete ||
usb_endpoint_xfer_isoc(dep->endpoint.desc)))
dep->flags &= ~DWC3_EP_BUSY;
@ -2107,6 +2115,14 @@ static void dwc3_endpoint_transfer_complete(struct dwc3 *dwc,
dwc->u1u2 = 0;
}
/*
* Our endpoint might get disabled by another thread during
* dwc3_gadget_giveback(). If that happens, we're just gonna return 1
* early on so DWC3_EP_BUSY flag gets cleared
*/
if (!dep->endpoint.desc)
return;
if (!usb_endpoint_xfer_isoc(dep->endpoint.desc)) {
int ret;