Re: [PATCH stable-5.15 2/3] usb: dwc3: qcom: fix use-after-free on runtime-PM wakeup

Greg Kroah-Hartman
2022-09-06T12:20:13Z

On Tue, Sep 06, 2022 at 02:07:01PM +0200, Johan Hovold wrote:
> From: Johan Hovold <johan+linaro@kernel.org>
>
> commit a872ab303d5ddd4c965f9cd868677781a33ce35a upstream.
>
> 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
> Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> Link: https://lore.kernel.org/r/20220804151001.23612-5-johan+linaro@kernel.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> [ johan: adjust context for 5.15 ]
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> ---
> drivers/usb/dwc3/dwc3-qcom.c | 14 +++++++++++++-
> drivers/usb/dwc3/host.c | 1 +
> 2 files changed, 14 insertions(+), 1 deletion(-)

This one did not apply to 5.4.y or 4.19.y :(