[debbugs-tracker] bug#27838: closed (grep error: "regexec.c:1375: pop_fail_stack: Assertion `num >= 0' failed.")

[GNU bug Tracking System]

Your message dated Wed, 26 Jul 2017 09:24:59 -0700
with message-id <address@hidden>
and subject line Re: bug#27838: grep error: "regexec.c:1375: pop_fail_stack: 
Assertion `num >= 0' failed."
has caused the debbugs.gnu.org bug report #27838,
regarding grep error: "regexec.c:1375: pop_fail_stack: Assertion `num >= 0' 
failed."
to be marked as done.

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27838: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=27838
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> --- Begin Message ---
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> Subject: 
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> grep error: "regexec.c:1375: pop_fail_stack: Assertion `num >= 0' failed."
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> Date: 
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> Wed, 26 Jul 2017 16:53:07 +0200
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> User-agent: 
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> Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1
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>
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> Hi,
>
> Try out the following test case, IIRC found with the aid of afl-fuzz:
>
> grep -E -f <( echo
> 'fzJ7fymOjgqOjgkfMnt/KSgfVzN8pFyQKR8zfGR7pGuQKR8zfCh8Mnt/KSgfVzN8pFyQKR8zfGR7pGuQKR8zfGR7kCkoCx8zfDJ7fymOrQmOjgkfM3wkXDI='
> | base64 -d ) /dev/null
> grep: regexec.c:1375: pop_fail_stack: Assertion `num >= 0' failed.
>
> I reported it once as on Fedora's Bugzilla, but got no reaction - in
> that case it even triggered a segmentation fault.
>
> Cheers,
> d33tah
>
>
>
> --- End Message ---

--- Begin Message --- Subject: Re: bug#27838: grep error: "regexec.c:1375: pop_fail_stack: Assertion `num >= 0' failed." Date: Wed, 26 Jul 2017 09:24:59 -0700 User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1

Thanks, that is due to an already known bug in glibc; see:

https://sourceware.org/bugzilla/show_bug.cgi?id=18986
https://debbugs.gnu.org/21513

To work around the problem with grep, use './configure --with-included-regex' when building grep, or encourage your upstream distributor to do so (or better yet, to fix glibc). You might also follow up on the glibc bug report to mention that the problem affects you too.

In the meantime I installed the attached patch, to add your test case to grep's test suite. The test is expected to fail if glibc regex is used.

0001-tests-add-Bug-27838-test-case.patch
Description: Text Data

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