Re: [platform-testers] bug#21755: new snapshot available: grep-2.21.82-fbc5

[Jim Meyering]

On Sun, Oct 25, 2015 at 4:02 PM, Bruce Dubbs <address@hidden> wrote:
> Paul Eggert wrote:
>>
>> Bruce Dubbs wrote:
>>>
>>> I would think that the tests in grep should account for both pcre and
>>> pcre2, at
>>> least for a couple of years.
>>
>>
>> Grep currently supports only PCRE.  I'd be surprised if it worked with
>> PCRE2.
>>
>> My test was with PCRE 8.35 with Debian and Ubuntu patches (I'm
>> up-to-date with Ubuntu 15.10 on x86-64).  Yours was with 8.37, I assume
>> with no patches. Perhaps if I find the time I can try building PCRE 8.37
>> on Ubuntu 15.10 and see whether it exhibits the bug, but to be honest I
>> was hoping someone else could debug this.  Perhaps you can try it with
>> 8.35 on linuxfromscratch?
>
>
> Yes, I can do that.  The main Upstream repo doesn't have 8.35, but it was at
> sourceforge.  I installed that:
>
> -rwxr-xr-x 1 root root 762440 Oct 25 17:43 /lib/libpcre.so.1.2.3
>
> but the pcre-jitstack test still aborts with a segfault.  I could try with a
> smaller pcrejit.txt file if that would help.
>
> OK, I think I have it.  I had a default ulimit:
>
> stack size              (kbytes, -s) 8192
>
> when I changed that to unlimited, the test passed.  More testing and ulimit
> -s 16000 fails but ulimit -s 32000 passes.

Thanks for investigating.
I wonder why your libpcre-8.37 needs so much stack and mine
(built from the release tarball by me, with no patch) segfaults only
when I restrict stack to less than about 50 KB.
I.e.,this exits with status 1:

  ( ulimit -s 50; LC_ALL=C src/grep -P -n '^([/](?!/)|[^/])*~/.*' pcrejit.txt )

but changing to a ulimit of 40 KB, it consistently segfaults.
That also jibes with what valgrind --tool=massif --stacks=yes reports.