From: "SZEDER Gábor" <szeder.dev@gmail.com>
To: "René Scharfe" <l.s.r@web.de>
Cc: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"Junio C Hamano" <gitster@pobox.com>,
"Git List" <git@vger.kernel.org>,
"Hamza Mahfooz" <someguy@effective-light.com>,
"Carlo Marcelo Arenas Belón" <carenas@gmail.com>,
"Andreas Schwab" <schwab@linux-m68k.org>
Subject: Re: [v2.35.0 regression] some PCRE hangs under UTF-8 locale (was: [PATCH 1/2] grep/pcre2: use PCRE2_UTF even with ASCII patterns)
Date: Sun, 6 Feb 2022 11:08:16 +0100 [thread overview]
Message-ID: <20220206100816.GA1936@szeder.dev> (raw)
In-Reply-To: <1425e548-c1bb-3cff-d75d-c3760abb6129@web.de>
On Sat, Feb 05, 2022 at 06:00:02PM +0100, René Scharfe wrote:
> >> --- >8 ---
> >> Subject: [PATCH] grep: disable JIT on PCRE2 before 10.36 to avoid endless loop
> >>
> >> Commit e0c6029 (Fix inifinite loop when a single byte newline is
> >> searched in JIT., 2020-05-29) of PCRE2 adds the following point to its
> >> ChangeLog for version 10.36:
> >>
> >> 2. Fix inifinite loop when a single byte newline is searched in JIT when
> >> invalid utf8 mode is enabled.
> >>
> >> Avoid that bug on older versions (which are still reportedly found in
> >> the wild) by disabling the JIT when handling UTF-8.
> >>
> >> Reported-by: SZEDER Gábor <szeder.dev@gmail.com>
> >> Signed-off-by: René Scharfe <l.s.r@web.de>
> >> ---
> >> Not sure how to test it. Killing git grep after a second or so seems a
> >> bit clumsy. timeout(1) from GNU coreutils at least allows doing that
> >> from the shell, but it's not a standard tool. Perhaps we need a new
> >> test helper for that purpose?
>
> https://mywiki.wooledge.org/BashFAQ/068 offers a Perl-based Shell
> function or aborting a program if it takes too long:
>
> doalarm() { perl -e 'alarm shift; exec @ARGV' -- "$@"; }
>
> It doesn't waste time when the program finishes faster and seems to work
> fine with git grep.
>
> I can't actually test the effectiveness of the patch because PCRE2's
> JIT doesn't work on my development machine at all (Apple M1), as I just
> discovered. :-/ While we know that disabling JIT helps, we didn't
> actually determine, yet, if e0c6029 (Fix inifinite loop when a single
> byte newline is searched in JIT., 2020-05-29) really fixes the "^\s"
> bug.
>
> So I have to abandon this patch, unfortunately. Any volunteer to pick
> it up?
FWIW, I built Git with your patch and USE_LIBPCRE2=YesPlease and run
the test suite, and it succeeded. Though I can't judge how much is
this actually worth.
next prev parent reply other threads:[~2022-02-06 10:08 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-18 19:50 [PATCH 1/2] grep/pcre2: use PCRE2_UTF even with ASCII patterns René Scharfe
2021-12-18 19:53 ` [PATCH 2/2] grep/pcre2: factor out literal variable René Scharfe
2021-12-19 19:37 ` Ævar Arnfjörð Bjarmason
2021-12-20 20:52 ` Junio C Hamano
2021-12-20 22:03 ` Ævar Arnfjörð Bjarmason
2021-12-20 20:53 ` Junio C Hamano
2021-12-20 20:47 ` Junio C Hamano
2022-01-29 17:25 ` [v2.35.0 regression] some PCRE hangs under UTF-8 locale (was: [PATCH 1/2] grep/pcre2: use PCRE2_UTF even with ASCII patterns) SZEDER Gábor
2022-01-30 7:55 ` René Scharfe
2022-01-30 9:04 ` SZEDER Gábor
2022-01-30 13:32 ` René Scharfe
2022-01-31 21:01 ` Ævar Arnfjörð Bjarmason
2022-02-05 17:00 ` René Scharfe
2022-02-06 10:08 ` SZEDER Gábor [this message]
2022-02-12 20:46 ` Ævar Arnfjörð Bjarmason
2022-02-17 21:14 ` René Scharfe
2022-02-17 22:56 ` [v2.35.0 regression] some PCRE hangs under UTF-8 locale Junio C Hamano
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