From: Thinh Nguyen Thinh.Nguyen@synopsys.com
commit 7441b273388b9a59d8387a03ffbbca9d5af6348c upstream.
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 Link: https://lore.kernel.org/r/8670aaf1cf52e7d1e6df2a827af2d77263b93b75.165638042... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/dwc3/gadget.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -3187,7 +3187,6 @@ static irqreturn_t dwc3_process_event_bu }
evt->count = 0; - evt->flags &= ~DWC3_EVENT_PENDING; ret = IRQ_HANDLED;
/* Unmask interrupt */ @@ -3200,6 +3199,9 @@ static irqreturn_t dwc3_process_event_bu 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; }