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SubjectRe: perf_fuzzer compiled for x32 causes reboot
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What is the instructions around it, by any chance?

On February 22, 2014 9:18:17 PM PST, Vince Weaver <vincent.weaver@maine.edu> wrote:
>On Fri, 21 Feb 2014, H. Peter Anvin wrote:
>
>> Error 6 reflects a write in userspace to a not-present page.
>>
>> Since your previous trace indicates that the value of the register in
>question
>> is a different one, I'm guessing that what we have here is PEBS
>getting
>> activated. 0x120 is 2*0x90, and 0x90 is the size of a 64-bit PEBS
>record.
>
>I'm having problems generating a replayable syscall trace that exhibits
>
>the problem.
>
>It turns out that the segfault address listed (the multiple of 0x120)
>happens to be the value in the RBP register at the time of the
>segfault.
>
>That's odd, as the instruction is
> movdqa %xmm0,(%rdi)
>and rdi is the valid mmap address of the perf ring buffer
> rdi 0xf7768000 4151738368
>
>so I'm not sure why RBP is involved at all.
>
>In all of the cases I've investigated the precise_ip value has been set
>
>for the problem event... but none of the events have been hardware
>events
>(software and breakpoint so far). So probably not PEBS related?
>
>Vince

--
Sent from my mobile phone. Please pardon brevity and lack of formatting.


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