In the Linux kernel, the following vulnerability has been resolved:
usb: dwc3: Wait unconditionally after issuing EndXfer command
Currently all controller IP/revisions except DWC3usb3 >= 310a wait 1ms unconditionally for ENDXFER completion when IOC is not set. This is because DWCusb3 controller revisions >= 3.10a supports GUCTL2[14: Rst_actbitlater] bit which allows polling CMDACT bit to know whether ENDXFER command is completed.
Consider a case where an IN request was queued, and parallelly softdisconnect was called (due to ffsepfilerelease). This eventually calls stopactivetransfer with IOC cleared, hence sendgadgetepcmd() skips waiting for CMDACT cleared during EndXfer. For DWC3 controllers with revisions >= 310a, we don't forcefully wait for 1ms either, and we proceed by unmapping the requests. If ENDXFER didn't complete by this time, it leads to SMMU faults since the controller would still be accessing those requests.
Fix this by ensuring ENDXFER completion by adding 1ms delay in _dwc3stopactivetransfer() unconditionally.