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usb: dwc3: qcom: fix use-after-free on runtime-PM wakeup

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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 2664deb093
("usb: dwc3: qcom: Honor wakeup enabled/disabled state"), which
incidentally also prevents this issue from being triggered.

Fixes: a4333c3a6b ("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>
This commit is contained in:
Johan Hovold 2022-08-04 17:09:56 +02:00 committed by Greg Kroah-Hartman
parent c06795f114
commit a872ab303d
2 changed files with 14 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
drivers/usb/dwc3/dwc3-qcom.c
View File

@ -298,6 +298,14 @@ static void dwc3_qcom_interconnect_exit(struct dwc3_qcom *qcom)
icc_put(qcom->icc_path_apps);
}
/* Only usable in contexts where the role can not change. */
static bool dwc3_qcom_is_host(struct dwc3_qcom *qcom)
{
struct dwc3 *dwc = platform_get_drvdata(qcom->dwc3);
return dwc->xhci;
}
static enum usb_device_speed dwc3_qcom_read_usb2_speed(struct dwc3_qcom *qcom)
{
struct dwc3 *dwc = platform_get_drvdata(qcom->dwc3);
@ -460,7 +468,11 @@ static irqreturn_t qcom_dwc3_resume_irq(int irq, void *data)
if (qcom->pm_suspended)
return IRQ_HANDLED;
if (dwc->xhci)
/*
* This is safe as role switching is done from a freezable workqueue
* and the wakeup interrupts are disabled as part of resume.
*/
if (dwc3_qcom_is_host(qcom))
pm_runtime_resume(&dwc->xhci->dev);
return IRQ_HANDLED;

1
drivers/usb/dwc3/host.c
View File

@ -135,4 +135,5 @@ err:
void dwc3_host_exit(struct dwc3 *dwc)
{
platform_device_unregister(dwc->xhci);
dwc->xhci = NULL;
}