On Wed, Aug 14, 2024, Faisal Hassan wrote:
On 8/14/2024 11:05 AM, Prashanth K wrote:
On 14-08-24 05:47 am, Thinh Nguyen wrote:
On Tue, Aug 13, 2024, Faisal Hassan wrote:
Null pointer dereference occurs when accessing 'hcd' to detect speed from dwc3_qcom_suspend after the xhci-hcd is unbound. To avoid this issue, ensure to check for NULL in dwc3_qcom_read_usb2_speed.
echo xhci-hcd.0.auto > /sys/bus/platform/drivers/xhci-hcd/unbind xhci_plat_remove() -> usb_put_hcd() -> hcd_release() -> kfree(hcd)
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000060 Call trace: dwc3_qcom_suspend.part.0+0x17c/0x2d0 [dwc3_qcom] dwc3_qcom_runtime_suspend+0x2c/0x40 [dwc3_qcom] pm_generic_runtime_suspend+0x30/0x44 __rpm_callback+0x4c/0x190 rpm_callback+0x6c/0x80 rpm_suspend+0x10c/0x620 pm_runtime_work+0xc8/0xe0 process_one_work+0x1e4/0x4f4 worker_thread+0x64/0x43c kthread+0xec/0x100 ret_from_fork+0x10/0x20
Fixes: c5f14abeb52b ("usb: dwc3: qcom: fix peripheral and OTG suspend") Cc: stable@vger.kernel.org Signed-off-by: Faisal Hassan quic_faisalh@quicinc.com
drivers/usb/dwc3/dwc3-qcom.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c index 88fb6706a18d..0c7846478655 100644 --- a/drivers/usb/dwc3/dwc3-qcom.c +++ b/drivers/usb/dwc3/dwc3-qcom.c @@ -319,13 +319,15 @@ static bool dwc3_qcom_is_host(struct dwc3_qcom *qcom) static enum usb_device_speed dwc3_qcom_read_usb2_speed(struct dwc3_qcom *qcom, int port_index) { struct dwc3 *dwc = platform_get_drvdata(qcom->dwc3);
What if dwc is not available?
Thats unlikely, dwc3_qcom_suspend() -> dwc3_qcom_is_host() checks for dwc, calls dwc3_qcom_read_usb2_speed() only if dwc is valid. But adding an extra check shouldn't cause harm.
Thanks Thinh and Prashanth for reviewing the patch. Since the caller is validating 'dwc', I think there is no need to recheck.
Ok. This is a bit hard to follow. The caller indirectly checks from dwc3_qcom_is_host() prior to calling this. Hopefully with the "flattening device" update, we can clean these up.
- struct usb_device *udev; + struct usb_device __maybe_unused *udev;
This is odd.... Is there a scenario where you don't want to set CONFIG_USB if dwc3_qcom is in use?
AFAIK this function is used to get the speeds of each ports, so that wakeup interrupts (dp/dm/ss irqs) can be configured accordingly before going to suspend, which is done during host mode only. So there shouldn't be any scenarios where CONFIG_USB isnt set when this is called.
From history I see CONFIG_USB was added to fix build issues for gadget only configuration. So configuration without CONFIG_USB also exists.
If it's gadget only, then it wouldn't be calling this function. The #ifdef CONFIG_USB guard placement can be reworked. But it shouldn't block this patch.
struct usb_hcd __maybe_unused *hcd; /* * FIXME: Fix this layering violation. */ hcd = platform_get_drvdata(dwc->xhci); + if (!hcd) + return USB_SPEED_UNKNOWN; #ifdef CONFIG_USB
Perhaps this #ifdef shouldn't only be checking this. But that's for another patch >> udev = usb_hub_find_child(hcd->self.root_hub, port_index + 1);
-- 2.17.1
Acked-by: Thinh Nguyen Thinh.Nguyen@synopsys.com
Thanks, Thinh