Commit 61a34885 authored by Uttkarsh Aggarwal's avatar Uttkarsh Aggarwal Committed by Greg Kroah-Hartman
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usb: dwc3: gadget: Fix NULL pointer dereference in dwc3_gadget_suspend 



In current scenario if Plug-out and Plug-In performed continuously
there could be a chance while checking for dwc->gadget_driver in
dwc3_gadget_suspend, a NULL pointer dereference may occur.

Call Stack:

	CPU1:                           CPU2:
	gadget_unbind_driver            dwc3_suspend_common
	dwc3_gadget_stop                dwc3_gadget_suspend
                                        dwc3_disconnect_gadget

CPU1 basically clears the variable and CPU2 checks the variable.
Consider CPU1 is running and right before gadget_driver is cleared
and in parallel CPU2 executes dwc3_gadget_suspend where it finds
dwc->gadget_driver which is not NULL and resumes execution and then
CPU1 completes execution. CPU2 executes dwc3_disconnect_gadget where
it checks dwc->gadget_driver is already NULL because of which the
NULL pointer deference occur.

Cc: stable@vger.kernel.org
Fixes: 9772b47a ("usb: dwc3: gadget: Fix suspend/resume during device mode")
Acked-by: default avatarThinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: default avatarUttkarsh Aggarwal <quic_uaggarwa@quicinc.com>
Link: https://lore.kernel.org/r/20240119094825.26530-1-quic_uaggarwa@quicinc.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent de4b5b28

drivers/usb/dwc3/gadget.c

+2 −4
Original line number Diff line number Diff line
@@ -4709,14 +4709,12 @@ int dwc3_gadget_suspend(struct dwc3 *dwc) 
	unsigned long flags;

	int ret;



	if (!dwc->gadget_driver)

		return 0;



	ret = dwc3_gadget_soft_disconnect(dwc);

	if (ret)

		goto err;



	spin_lock_irqsave(&dwc->lock, flags);

	if (dwc->gadget_driver)

		dwc3_disconnect_gadget(dwc);

	spin_unlock_irqrestore(&dwc->lock, flags);