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usb: dwc3: gadget: Fix NULL pointer dereference in dwc3_gadget_suspend

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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: 9772b47a4c ("usb: dwc3: gadget: Fix suspend/resume during device mode")
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Uttkarsh Aggarwal <quic_uaggarwa@quicinc.com>
Link: https://lore.kernel.org/r/20240119094825.26530-1-quic_uaggarwa@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Uttkarsh Aggarwal 2024-01-19 15:18:25 +05:30 committed by Greg Kroah-Hartman
parent de4b5b28c8
commit 61a348857e
1 changed files with 2 additions and 4 deletions
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4
drivers/usb/dwc3/gadget.c
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@ -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);