Messages in this thread | | | Subject | Re: perf_fuzzer compiled for x32 causes reboot | From | "H. Peter Anvin" <> | Date | Sat, 22 Feb 2014 22:07:50 -0800 |
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I'd be interested in how rbp gets set, too. It might just be a coincidence and the value in rbp has some other meaning here.
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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