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Commit fbe0a6d1 authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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usb: dwc3: qcom: fix use-after-free on runtime-PM wakeup 



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: a4333c3a ("usb: dwc3: Add Qualcomm DWC3 glue driver")
Cc: stable@vger.kernel.org      # 4.18
Reviewed-by: default avatarMatthias Kaehlcke <mka@chromium.org>
Reviewed-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: default avatarJohan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20220804151001.23612-5-johan+linaro@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
[ johan: adjust context for 5.4 ]
Signed-off-by: default avatarJohan Hovold <johan+linaro@kernel.org>
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 83dd5895

drivers/usb/dwc3/dwc3-qcom.c

+13 −1
Original line number Diff line number Diff line
@@ -173,6 +173,14 @@ static int dwc3_qcom_register_extcon(struct dwc3_qcom *qcom) 
	return 0;

}



/* 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 void dwc3_qcom_disable_interrupts(struct dwc3_qcom *qcom)

{

	if (qcom->hs_phy_irq) {
@@ -280,7 +288,11 @@ 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;

drivers/usb/dwc3/host.c

+1 −0
Original line number Diff line number Diff line
@@ -142,4 +142,5 @@ void dwc3_host_exit(struct dwc3 *dwc) 
	phy_remove_lookup(dwc->usb3_generic_phy, "usb3-phy",

			  dev_name(dwc->dev));

	platform_device_unregister(dwc->xhci);

	dwc->xhci = NULL;

}