Subject: Re: bug#23983: [PATCH] grep: fix crash with a pattern of alternation of two same characters

From: Eric Blake <[email-masked]>
Date: Thu, 14 Jul 2016 11:28:56 -0600

On 07/14/2016 09:07 AM, Norihiro Tanaka wrote:
> Current master crashes with below.
> 
> $ printf '0\n0' >pat
> $ printf '0\n' >in
> $ env LC_ALL=C grep -F pat in
> 
> grep -F uses memchr2() for each character in this pattern, but if two
> characters is same, the trie has no child.

memchr2() should already be handling the special case of the same
character requested twice, without clients having to code around it.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org