lkml.org 
[lkml]   [2014]   [Sep]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: perf: perf_fuzzer triggers instant reboot
On Wed, 10 Sep 2014, Peter Zijlstra wrote:
>
> Sasha reported something from his KVM based fuzzing, maybe that's the
> same. But that x86_exceptions thing is interesting, lemme go look at
> that first.

that's what got me looking at things again, the trinity reports. Though I
think those involve CPU hotplugging which my fuzzer shouldn't trigger.

I do think this is the same memory corruption/reboot bug that I reported
back in February (the thread is "perf_fuzzer compiled for x32 causes
reboot" but I wasn't able to isolate the problem then either.

Somehow something is stomping over memory with a forking workload (likely
an improper free with RCU like we've seen before) but the fact that it
causes a reboot immediately makes it *really* hard to debug this.


I'm not sure about the tracing issue, possibly it's just a side effect of
memory being corrupted by the same bug. In case it's relevant here's the
trace-cmd I was trying to use:

trace-cmd record -e raw_syscalls -p function -l '*perf*' -n 'perf_event_task_tick' -l 'x86*' -l 'intel*' -P 2807

Vince


\
 
 \ /
  Last update: 2014-09-10 15:41    [W:0.063 / U:1.584 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site