commit 6856d30 (usb: dwc3: ep0: return early
on NULL requests) tried to fix a minor corner
case where we could dereference a NULL pointer
but it also ended up introducing some dead code.
Unfortunately, that dead code, if reached, could
end up starving the endpoint request list because
a request would never be given back when it should.
Fix this by moving the check for empty request list
before its first use.
Reported-by: Dave Jones <davej@xxxxxxxxxx>
Signed-off-by: Felipe Balbi <balbi@xxxxxx>
---
drivers/usb/dwc3/ep0.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 711b230..df38e7e 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -791,6 +791,10 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
trb = dwc->ep0_trb;
+ r = next_request(&ep0->request_list);
+ if (!r)
+ return;
+
status = DWC3_TRB_SIZE_TRBSTS(trb->size);
if (status == DWC3_TRBSTS_SETUP_PENDING) {
dwc3_trace(trace_dwc3_ep0, "Setup Pending received");
@@ -801,10 +805,6 @@ static void dwc3_ep0_complete_data(struct dwc3 *dwc,
return;
}
- r = next_request(&ep0->request_list);
- if (!r)
- return;
-
ur = &r->request;
length = trb->size & DWC3_TRB_SIZE_MASK;
--
2.1.0.GIT
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