Regular oops on shutdown of KVM/ARM64 machines with VGA device

Dirk Müller dirk at
Tue Jun 30 00:46:28 PDT 2015

Hi Mark,

> I've seen issues with prior FW versions where the ethernet controller
> was erroneously left active after ExitBootServices(), and would DMA
> braodcast packets over the kernel. That resulted in similar failures to
> what you're reporting.
> Can you reproduce the issue with all ethernet cables unplugged?

not with ethernet cables unplugged, but I did ifdown on all interfaces
and was able to trigger the issue just fine. Please note it is 100%
reproducible in one sequence each and every time, which imho makes it
unlikely to be a DMA scatter issue.

> You can also try enabling CONFIG_MEMTEST (and pass memtest on the
> command line) at boot time, which may happen to catch DMA in the act.

Did not try this.


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