GNU bug report logs - #19833
grep: internal PCRE error: -27 since updating from 2.16 to 2.21

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From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Oliver Freyermuth <o.freyermuth <at> googlemail.com>
Subject: bug#19833: closed (Re: bug#19833: grep: internal PCRE error: -27
 since updating from 2.16 to 2.21)
Date: Wed, 11 Feb 2015 07:50:03 +0000

[Message part 1 (text/plain, inline)]

Your bug report

#19833: grep: internal PCRE error: -27 since updating from 2.16 to 2.21

which was filed against the grep package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to 19833 <at> debbugs.gnu.org.

-- 
19833: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=19833
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems

[Message part 2 (message/rfc822, inline)]

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Oliver Freyermuth <o.freyermuth <at> googlemail.com>, 
 19833-done <at> debbugs.gnu.org
Subject: Re: bug#19833: grep: internal PCRE error: -27 since updating from
 2.16 to 2.21
Date: Tue, 10 Feb 2015 23:49:17 -0800

[Message part 3 (text/plain, inline)]

Thanks for the bug report and test case.  I installed the attached patch, which 
fixed the bug for me, and which adds a similar test case to the test database.

[0001-Grow-the-JIT-stack-if-it-becomes-exhausted.patch (text/x-patch, attachment)]

[Message part 5 (message/rfc822, inline)]

From: Oliver Freyermuth <o.freyermuth <at> googlemail.com>
To: bug-grep <at> gnu.org
Subject: grep: internal PCRE error: -27 since updating from 2.16 to 2.21
Date: Tue, 10 Feb 2015 22:59:38 +0100

[Message part 6 (text/plain, inline)]

Dear grep'pers,

since I updated from 2.16 to 2.21, several of my "check list of files
for bad filenames"-style grep expressions fail like this:
grep: internal PCRE error: -27
(one of the failing examples follows at the end of the mail, example
filename-list attached)

Researching this, I found that -27 is PCRE_ERROR_JIT_STACKLIMIT.
Apparently I exceed the 512 K JIT-stack-limit which is hardcoded in grep
with several of my regexps.

As using the JIT can not be turned off at runtime, nor can the stacksize
be controlled without patching + recompiling, this breaks previously
working expressions for me, so I consider this a new regression,
introduced with b06f7a29a58bbdd5866afc1e92dba3fdc9e2ed59 .

I tested that increasing the stack-size to 1 M fixes the problem for me.
A better fix could maybe consist of a better error message, allowing
stack-size control at runtime and / or making JIT optional at runtime.


Reproducer, using the attached file (which is generated by a find
command, of course - only 637 files with absolute paths in plain ASCII):
$ LANG=C grep -P -n '^([/](?!/)|[^/])*~/.*' pcrejit.txt
grep: internal PCRE error: -27


Cheers,
	Oliver

[pcrejit.txt (text/plain, attachment)]

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