Messages in this thread | | | Date | Thu, 27 Feb 2014 15:46:52 -0800 | From | "H. Peter Anvin" <> | Subject | Re: perf_fuzzer compiled for x32 causes reboot |
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On 02/27/2014 03:30 PM, Steven Rostedt wrote: > On Thu, 27 Feb 2014 14:52:54 -0800 > "H. Peter Anvin" <hpa@zytor.com> wrote: > >> On 02/27/2014 02:31 PM, Steven Rostedt wrote: >>> >>> Yeah, something is getting mesed up. >>> >> >> What it *looks* like to me is that we try to nest the cr2 save/restore, >> which doesn't nest because it is a percpu variable. >> >> ... except in the x86-64 case, we *ALSO* save/restore cr2 inside >> entry_64.S, which makes the stuff in do_nmi completely redundant and >> there for no good reason. > > Peter, look at the code. That percpu cr2 is in a #ifdef CONFIG_X86_32 > section. That is, it isn't even executed. That's i386 code. The only > place the cr2 is saved for x86_64 is in entry_64.S. >
Right, egg on my face. However, I still think it would make more sense for it to nest the way entry_64.S does if at all possible.
That makes this even more confusing, though. I would still like to see what happens with the patch I sent Vince.
-hpa
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