Subject: bug#22793: grep -E assertion failure with back references

From: [email-masked]
Date: Wed, 24 Feb 2016 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\2\1'
grep: regexec.c:1401: pop_fail_stack: Assertion `num >= 0' failed.

More info at: https://bugs.debian.org/186568

Regards,

Santiago