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Re: recent buildbot fuzz failures
From: Evan Huus <eapache () gmail com>
Date: Sun, 27 Jan 2013 11:38:16 -0500

On Thu, Jan 24, 2013 at 12:58 PM, Gerald Combs <gerald () wireshark org> wrote:
On 1/23/13 7:46 PM, Jeff Morriss wrote:
Hi Gerald,

The buildbot's been generating a lot of fuzz failure bugs recently--none
of which I've been able to reproduce in any of the supported trunks
(Valgrind is silent too).

Any idea what's going on?

The last fuzz failure log says this (which doesn't make sense):

    /home/wireshark/menagerie/menagerie/9460-test.pcap: (-nVxr) (-nr)  OK

ls: cannot access
/dev/shm/buildbot/clangcodeanalysis/menagerie-fuzz/fuzz-*.pcap: No
such file or directory

In order to improve performance and reduce the I/O load I've been using
/dev/shm (which uses tmpfs) as the temporary directory for fuzzing.
However, it looks like the contents of /dev/shm disappear and reappear
periodically. The buildbots complain about missing files but when I
check they're there. I'm not sure what's causing it. Maybe a cron job or
daemon periodically clobbers and un-clobbers /dev/shm?

I moved fuzzing to its own mount point. Hopefully Buildbot will stop
complaining.

Another thing perhaps worth trying is to invert the loop over passes
with the loop over files. Instead of fuzzing each file once and then
starting over, it would do the first file n times, then the second
file n times, etc. which would mean that each file is hot in cache for
all but the first pass.

Cheers,
Evan
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