On Thu, Aug 04, 2022 at 05:09:56PM +0200, Johan Hovold wrote:
The Qualcomm dwc3 runtime-PM implementation checks the xhci platform-device pointer in the wakeup-interrupt handler to determine whether the controller is in host mode and if so triggers a resume.
After a role switch in OTG mode the xhci platform-device would have been freed and the next wakeup from runtime suspend would access the freed memory.
Note that role switching is executed from a freezable workqueue, which guarantees that the pointer is stable during suspend.
Also note that runtime PM has been broken since commit 2664deb09306 ("usb: dwc3: qcom: Honor wakeup enabled/disabled state"), which incidentally also prevents this issue from being triggered.
Fixes: a4333c3a6ba9 ("usb: dwc3: Add Qualcomm DWC3 glue driver") Cc: stable@vger.kernel.org # 4.18 Signed-off-by: Johan Hovold johan+linaro@kernel.org
Reviewed-by: Matthias Kaehlcke mka@chromium.org