Re: [PATCH v2 4/9] usb: dwc3: qcom: fix use-after-free on runtime-PM wakeup

[Matthias Kaehlcke]

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@xxxxxxxxxxxxxxx      # 4.18
> Signed-off-by: Johan Hovold <johan+linaro@xxxxxxxxxx>

Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>