Monday, October 21, 2013

My troubleshooting led to discovering a Windows 8.1 bug!

Upon analyzing a crash as usual, I came upon an 8.1 case in which the user was experiencing USBXHCI.SYS crashes. I took a quick look at the modules list and determined that the driver emusba10.sys (E-MU USB-Audio 1.0 driver) was the probable cause as it was dated from 2010 and was all I had to go on in terms of USB related devices and or software on this system.

Sure enough, a Microsoft engineer posted and eventually investigated the issue and determined:

Based on my investigation, this appears to be a bug in emusba10.sys driver from Creative Labs . This driver is sending a malformed URB. Windows 8 validated the URB before processing. This validation was removed in Windows 8.1 as part of some optimization. Until we come up with resolution for this, please don't plug this device to USB 3.0 port / blue port. Sorry for the inconvenience. 

With this said, if any BSOD analysts come across an 8.1 (or 8) based system with USBXHCI.SYS crashes, check the modules list for emusba10.sys and let them know it's a known bug.

Thread itself - BSOD with DRIVER_IRQL_NOT_LESS_OR_EQUAL in USBXHCI.SYS when watching - Microsoft Community

I am not sure if I am being overzealous, but it feels pretty cool being part of the reason a bug was discovered!

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