[PATCH 2/2] USB: dwc3: fix use-after-free on core driver unbind

[Johan Hovold <johan+linaro@kernel.org>]

Some dwc3 glue drivers are currently accessing the driver data of the
child core device directly, which is clearly a bad idea as the child may
not have probed yet or may have been unbound from its driver.

As a workaround until the glue drivers have been fixed, clear the driver
data pointer before allowing the glue parent device to runtime suspend
to prevent its driver from accessing data that has been freed during
unbind.

Fixes: 6dd2565989b4 ("usb: dwc3: add imx8mp dwc3 glue layer driver")
Fixes: 6895ea55c385 ("usb: dwc3: qcom: Configure wakeup interrupts during suspend")
Cc: stable@vger.kernel.org      # 5.12
Cc: Li Jun <jun.li@nxp.com>
Cc: Sandeep Maheswaram <quic_c_sanm@quicinc.com>
Cc: Krishna Kurapati <quic_kriskura@quicinc.com>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/usb/dwc3/core.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 7b2ce013cc5b..d68958e151a7 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1929,6 +1929,11 @@ static int dwc3_remove(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_dont_use_autosuspend(&pdev->dev);
 	pm_runtime_put_noidle(&pdev->dev);
+	/*
+	 * HACK: Clear the driver data, which is currently accessed by parent
+	 * glue drivers, before allowing the parent to suspend.
+	 */
+	platform_set_drvdata(pdev, NULL);
 	pm_runtime_set_suspended(&pdev->dev);
 
 	dwc3_free_event_buffers(dwc);
-- 
2.39.3