| Message ID | 8670aaf1cf52e7d1e6df2a827af2d77263b93b75.1656380429.git.Thinh.Nguyen@synopsys.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 7441b273388b9a59d8387a03ffbbca9d5af6348c |
| Headers | show |
| Series | usb: dwc3: gadget: Fix event pending check | expand |
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 8716bece1072..0d89dfa6eef5 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -4249,7 +4249,6 @@ static irqreturn_t dwc3_process_event_buf(struct dwc3_event_buffer *evt) } evt->count = 0; - evt->flags &= ~DWC3_EVENT_PENDING; ret = IRQ_HANDLED; /* Unmask interrupt */ @@ -4261,6 +4260,9 @@ static irqreturn_t dwc3_process_event_buf(struct dwc3_event_buffer *evt) dwc3_writel(dwc->regs, DWC3_DEV_IMOD(0), dwc->imod_interval); } + /* Keep the clearing of DWC3_EVENT_PENDING at the end */ + evt->flags &= ~DWC3_EVENT_PENDING; + return ret; }
The DWC3_EVENT_PENDING flag is used to protect against invalid call to top-half interrupt handler, which can occur when there's a delay in software detection of the interrupt line deassertion. However, the clearing of this flag was done prior to unmasking the interrupt line, creating opportunity where the top-half handler can come. This breaks the serialization and creates a race between the top-half and bottom-half handler, resulting in losing synchronization between the controller and the driver when processing events. To fix this, make sure the clearing of the DWC3_EVENT_PENDING is done at the end of the bottom-half handler. Fixes: d325a1de49d6 ("usb: dwc3: gadget: Prevent losing events in event cache") Cc: stable@vger.kernel.org Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com> --- drivers/usb/dwc3/gadget.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) base-commit: 03c765b0e3b4cb5063276b086c76f7a612856a9a