GNU bug report logs - #22793
grep -E assertion failure with back references

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: santiagorr <at> riseup.net
To: bug-grep <at> gnu.org
Subject: grep -E assertion failure with back references
Date: 2016年2月24日 17:18:54 +0100

Hi,
This is a long standing bug reported to Debian, still present in 2.23.
It was forwarded at some point, but I cannot find any reference, so I'm
reforwarding it.
% echo abc | LANG=C grep -E '(.*)(.*)(.*)3円2円1円'
grep: regexec.c:1401: pop_fail_stack: Assertion `num >= 0' failed.
More info at: https://bugs.debian.org/186568
Regards,
Santiago

Message #8 received at 22793 <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: santiagorr <at> riseup.net
Cc: 22793 <at> debbugs.gnu.org
Subject: Re: bug#22793: grep -E assertion failure with back references
Date: 2016年2月24日 10:56:38 -0800

forcemerge 21513 22793
thanks
On Wed, Feb 24, 2016 at 8:18 AM, <santiagorr <at> riseup.net> wrote:
> Hi,
>
> This is a long standing bug reported to Debian, still present in 2.23.
> It was forwarded at some point, but I cannot find any reference, so I'm
> reforwarding it.
>
> % echo abc | LANG=C grep -E '(.*)(.*)(.*)3円2円1円'
> grep: regexec.c:1401: pop_fail_stack: Assertion `num >= 0' failed.
>
> More info at: https://bugs.debian.org/186568
Correct, this was reported some time ago,
both here and in the upstream glibc bugzilla:
 http://bugs.gnu.org/21513
 https://sourceware.org/bugzilla/show_bug.cgi?id=18986
There is currently an "XFAIL" (expected-to-fail) test in grep's
test suite that exercises precisely this bug:
 git.savannah.gnu.org/cgit/grep.git/tree/tests/triple-backref

Message #13 received at 22793 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Jim Meyering <jim <at> meyering.net>, santiagorr <at> riseup.net
Cc: 22793 <at> debbugs.gnu.org, 186568 <at> bugs.debian.org
Subject: Re: bug#22793: grep -E assertion failure with back references
Date: 2016年2月24日 11:46:55 -0800

With recent 'grep' you can work around the problem by configuring 
--with-included-regex. That has some other undesirable properties, though.
This is really a glibc bug 
<https://sourceware.org/bugzilla/show_bug.cgi?id=18986> and the glibc 
patch could be applied to the Debian copy of glibc. Here's the patch:
http://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=5513b40999149090987a0341c018d05d3eea1272
In other words, Debian bug #186568 is really a glibc bug, not a grep 
bug. Can you please fix the Debian bug report accordingly? I'll CC: this 
message there.

Message #16 received at 22793 <at> debbugs.gnu.org (full text, mbox):

From: arnold <at> skeeve.com
To: santiagorr <at> riseup.net, jim <at> meyering.net, eggert <at> cs.ucla.edu
Cc: 22793 <at> debbugs.gnu.org, 186568 <at> bugs.debian.org
Subject: Re: bug#22793: grep -E assertion failure with back references
Date: 2016年2月24日 23:12:10 -0700

Paul Eggert <eggert <at> cs.ucla.edu> wrote:
> With recent 'grep' you can work around the problem by configuring 
> --with-included-regex.
Not so. I did a fresh
	./boostrap
	./configure --with-included-regex
	make
and it still core dumps:
$ echo abc | ./src/grep -E '(.*)(.*)(.*)3円2円1円'
grep: regexec.c:1413: pop_fail_stack: Assertion `((Idx) (num) < ((Idx) -2))' failed.
Aborted (core dumped)
I looked at it in a debugger fs->num before the --fs->num executes looks to
be -1.
Thanks,
Arnold

Message #21 received at 22793 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: arnold <at> skeeve.com, santiagorr <at> riseup.net, jim <at> meyering.net
Cc: 22793 <at> debbugs.gnu.org, 186568 <at> bugs.debian.org, 21513 <at> debbugs.gnu.org
Subject: Re: bug#22793: grep -E assertion failure with back references
Date: 2016年2月25日 00:01:52 -0800

arnold <at> skeeve.com wrote:
> Paul Eggert <eggert <at> cs.ucla.edu> wrote:
>
>> With recent 'grep' you can work around the problem by configuring
>> --with-included-regex.
>
> Not so. I did a fresh
>
> 	./boostrap
> 	./configure --with-included-regex
> 	make
>
> and it still core dumps:
>
> $ echo abc | ./src/grep -E '(.*)(.*)(.*)3円2円1円'
> grep: regexec.c:1413: pop_fail_stack: Assertion `((Idx) (num) < ((Idx) -2))' failed.
> Aborted (core dumped)
>
> I looked at it in a debugger fs->num before the --fs->num executes looks to
> be -1.
Sorry, you're right. I got confused into thinking that grep Bug#22793 and grep 
Bug#21513 are the same bugs, but they're not. I have unmerged them.
This is still a glibc bug, not a grep bug; it's just that we don't have a fix.
grep Bug#21513 is indeed fixed by configuring --with-included-regex.

Message #24 received at 22793 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: 22793 <at> debbugs.gnu.org
Cc: Paolo Bonzini <bonzini <at> gnu.org>, arnold <at> skeeve.com, santiagorr <at> riseup.net,
 Jim Meyering <jim <at> meyering.net>
Subject: Re: grep -E assertion failure with back references
Date: 2017年1月17日 13:37:12 -0800

> This is still a glibc bug, not a grep bug; it's just that we don't have a fix.
I finally got around to finding the correct glibc bug report for this
grep bug. Here it is:
https://sourceware.org/bugzilla/show_bug.cgi?id=11053
I added a comment to the glibc bug, saying that it causes grep Bug#22793
<https://bugs.gnu.org/22793>.
Paolo Bonzini reported the glibc bug in 2009 and is the current
assignee. I think he's pretty busy doing other things. It'd be nice if
someone could fix the glibc bug (or at least, fix it in Gnulib), though
I suspect that any fix will not be trivial.

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