From: Johan Hovold <johan+linaro@xxxxxxxxxx>
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@xxxxxxxxxxxxxxx # 4.18
Reviewed-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
Signed-off-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220804151001.23612-5-johan+linaro@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
[ johan: adjust context for 5.4 ]
Signed-off-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
drivers/usb/dwc3/dwc3-qcom.c | 14 +++++++++++++-
drivers/usb/dwc3/host.c | 1 +
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
index 5bb5384f3612..9d5320562e81 100644
--- a/drivers/usb/dwc3/dwc3-qcom.c
+++ b/drivers/usb/dwc3/dwc3-qcom.c
@@ -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;
diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c
index 1a3878a3be78..124e9f80dccd 100644
--- a/drivers/usb/dwc3/host.c
+++ b/drivers/usb/dwc3/host.c
@@ -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;
}
--
2.35.1
