GNU bug report logs - #17516
[PATCH] grep: no count newline at the head of a text buffer

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

From: Norihiro Tanaka <noritnk <at> kcn.ne.jp>
To: bug-grep <at> gnu.org
Subject: [PATCH] grep: no count newline at the head of a text buffer
Date: Sat, 17 May 2014 10:20:51 +0900

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

Severity: critical

When cleared caches of transition tables, number of newline is counted
incorrectly, As a result, grep may crash.

I confirmed crash of grep with a text case in bug#15191

  http://dobrokot.ru/dump/slow_dfa_merge.2013-08-26.tar.gz

  $ env LC_ALL=C time -p src/egrep -f regex.re input_lines.txt

When `p' is beginning, p[-1] is out of the buffer.  Therefore, we
shouldn't count it.

Norihiro

[0001-grep-no-count-newline-at-the-head-of-a-text-buffer.patch (application/octet-stream, attachment)]

Message #10 received at 17516-done <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Norihiro Tanaka <noritnk <at> kcn.ne.jp>, 17516-done <at> debbugs.gnu.org
Subject: Re: bug#17516: [PATCH] grep: no count newline at the head of a text
 buffer
Date: Fri, 16 May 2014 22:08:41 -0700

Thanks for catching that; I installed the patch with a slightly reworded 
ChangeLog entry.

Message #13 received at 17516 <at> debbugs.gnu.org (full text, mbox):

From: Norihiro Tanaka <noritnk <at> kcn.ne.jp>
To: 17516 <at> debbugs.gnu.org
Cc: Paul Eggert <eggert <at> cs.ucla.edu>, jim <at> meyering.net
Subject: Re: bug#17516: [PATCH] grep: no count newline at the head of a text
 buffer
Date: Sun, 18 May 2014 07:59:12 +0900

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

Thanks for the review and push.

I also submit a test case for this bug.  It fails in grep-2.18.146-ebf3,
and succeeds in current master.

[0001-tests-add-test-case-previous-fix-previous-change.patch (text/plain, attachment)]

Message #16 received at 17516 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Norihiro Tanaka <noritnk <at> kcn.ne.jp>, 17516 <at> debbugs.gnu.org
Cc: jim <at> meyering.net
Subject: Re: bug#17516: [PATCH] grep: no count newline at the head of a text
 buffer
Date: Sat, 17 May 2014 17:29:52 -0700

Norihiro Tanaka wrote:

> I also submit a test case for this bug.

Thanks, I installed that.

Message #19 received at 17516 <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: Norihiro Tanaka <noritnk <at> kcn.ne.jp>
Cc: Paul Eggert <eggert <at> cs.ucla.edu>, 17516 <at> debbugs.gnu.org
Subject: Re: bug#17516: [PATCH] grep: no count newline at the head of a text
 buffer
Date: Wed, 21 May 2014 21:34:02 -0700

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

On Sat, May 17, 2014 at 3:59 PM, Norihiro Tanaka <noritnk <at> kcn.ne.jp> wrote:
> Thanks for the review and push.
>
> I also submit a test case for this bug.  It fails in grep-2.18.146-ebf3,
> and succeeds in current master.

Thanks again.
However, that new test made it so "make syntax-check" would fail.
I've suppressed that new failure via the attached:

[0001-maint-avoid-new-false-positive-syntax-check-failure.patch (application/octet-stream, attachment)]

Message #22 received at 17516 <at> debbugs.gnu.org (full text, mbox):

From: Eric Blake <eblake <at> redhat.com>
To: Jim Meyering <jim <at> meyering.net>, Norihiro Tanaka <noritnk <at> kcn.ne.jp>
Cc: Paul Eggert <eggert <at> cs.ucla.edu>, 17516 <at> debbugs.gnu.org
Subject: Re: bug#17516: [PATCH] grep: no count newline at the head of a text
 buffer
Date: Wed, 21 May 2014 22:52:30 -0600

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

On 05/21/2014 10:34 PM, Jim Meyering wrote:
> On Sat, May 17, 2014 at 3:59 PM, Norihiro Tanaka <noritnk <at> kcn.ne.jp> wrote:
>> Thanks for the review and push.
>>
>> I also submit a test case for this bug.  It fails in grep-2.18.146-ebf3,
>> and succeeds in current master.
> 
> Thanks again.
> However, that new test made it so "make syntax-check" would fail.
> I've suppressed that new failure via the attached:

It's also possible to rewrite the line:

grep -f in 'in' >out || fail=1

so as to avoid needing the suppression (I'm not sure which is prettier).

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

[signature.asc (application/pgp-signature, attachment)]

Message #25 received at 17516 <at> debbugs.gnu.org (full text, mbox):

From: Jim Meyering <jim <at> meyering.net>
To: Eric Blake <eblake <at> redhat.com>
Cc: Paul Eggert <eggert <at> cs.ucla.edu>, Norihiro Tanaka <noritnk <at> kcn.ne.jp>,
 17516 <17516 <at> debbugs.gnu.org>
Subject: Re: bug#17516: [PATCH] grep: no count newline at the head of a text
 buffer
Date: Wed, 21 May 2014 21:55:30 -0700

On Wed, May 21, 2014 at 9:52 PM, Eric Blake <eblake <at> redhat.com> wrote:
> On 05/21/2014 10:34 PM, Jim Meyering wrote:
>> On Sat, May 17, 2014 at 3:59 PM, Norihiro Tanaka <noritnk <at> kcn.ne.jp> wrote:
>>> Thanks for the review and push.
>>>
>>> I also submit a test case for this bug.  It fails in grep-2.18.146-ebf3,
>>> and succeeds in current master.
>>
>> Thanks again.
>> However, that new test made it so "make syntax-check" would fail.
>> I've suppressed that new failure via the attached:
>
> It's also possible to rewrite the line:
>
> grep -f in 'in' >out || fail=1
>
> so as to avoid needing the suppression (I'm not sure which is prettier).

Thanks for the suggestion.
Since this is a false-positive after all, I prefer to keep the
work-around out of the primary source file, even if that
means exempting this entire file from that one syntax-check.
It is unlikely to matter.

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