Messages in this thread | | | Date | Sun, 29 Dec 2013 17:18:44 -0800 | From | "H. Peter Anvin" <> | Subject | Re: Sanitize CPU-state when switching from virtual-8086 mode to other task |
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On 12/29/2013 12:44 PM, halfdog wrote: > H. Peter Anvin wrote: >> On 12/28/2013 02:02 PM, halfdog wrote: >>> It seems that missing CPU-state sanitation during task >>> switching triggers kernel-panic. This might be related to >>> unhandled FPU-errors. See [1] for POC and serial console log >>> of OOPs. Due to missing real 32-bit x86-hardware it is not >>> clear, if this issue might be related to subtle differences in >>> virtual-8086 mode handling when inside a virtualbox guest. >>> > >> This oops happens inside the guest? Either way, I would be >> *very* skeptical of Virtualbox in this case. > >> You can run a 32-bit kernel on 64-bit hardware, you know... > > I know, but hardware was occupied with long-running simulation. > > With the initial POC, there might be a timing issue involved, with > different process layout, exception does not occur in swith_to but > sometimes on other locations. > > I created a new random-code testcase [1] , which works around that > problem. When booted a Debian initrd and tried id, OOPSes are > fired like wild but at least system does not lock up immediately. >
Still in VirtualBox?
-hpa
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