diff options
| author | Johan Hovold <johan+linaro@kernel.org> | 2022-08-04 10:52:46 +0200 |
|---|---|---|
| committer | Johan Hovold <johan+linaro@kernel.org> | 2022-08-30 13:32:46 +0200 |
| commit | 67c3e3df2dbbf12f49288ddc4a1ef6554e86c231 (patch) | |
| tree | 4a072df215e05bbe70c6e5947d441b3f3185c991 | |
| parent | 78ecfeb918ab372a88ac86024912108452786c5d (diff) | |
usb: dwc3: qcom: fix use-after-free on runtime-PM wakeup
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>
---
Changes in v2
- new patch
Changes in v3
- add Matthia's and Mani's tags
| -rw-r--r-- | drivers/usb/dwc3/dwc3-qcom.c | 14 | ||||
| -rw-r--r-- | drivers/usb/dwc3/host.c | 1 |
2 files changed, 14 insertions, 1 deletions
diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c index e9364141661b..6884026b9fad 100644 --- a/drivers/usb/dwc3/dwc3-qcom.c +++ b/drivers/usb/dwc3/dwc3-qcom.c @@ -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; diff --git a/drivers/usb/dwc3/host.c b/drivers/usb/dwc3/host.c index f56c30cf151e..f6f13e7f1ba1 100644 --- a/drivers/usb/dwc3/host.c +++ b/drivers/usb/dwc3/host.c @@ -135,4 +135,5 @@ err: void dwc3_host_exit(struct dwc3 *dwc) { platform_device_unregister(dwc->xhci); + dwc->xhci = NULL; } |