From: Konstantin Tokarev <annulen@yandex.ru>
To: "SZEDER Gábor" <szeder.dev@gmail.com>,
"Alexandr Miloslavskiy" <alexandr.miloslavskiy@syntevo.com>
Cc: Ondrej Pohorelsky <opohorel@redhat.com>,
"git@vger.kernel.org" <git@vger.kernel.org>
Subject: Re: git-core: try_to_follow_renames(): git killed by SIGSEGV
Date: Tue, 10 Mar 2020 20:30:05 +0300 [thread overview]
Message-ID: <347951583861239@vla5-dcf36e533bf7.qloud-c.yandex.net> (raw)
In-Reply-To: <20200310165723.GB3122@szeder.dev>
10.03.2020, 19:57, "SZEDER Gábor" <szeder.dev@gmail.com>:
> On Fri, Mar 06, 2020 at 03:44:34PM +0100, Alexandr Miloslavskiy wrote:
>> Since I like studying crashes and noone else replied, I decided to have a
>> look.
>>
>> The problem is easy to reproduce with this (replace 1.c with any file):
>> git log --follow -L 1,1:1.c -- 1.c
>
> Don't do this. In particular:
>
> - Don't use line-level log with a pathspec, because the
> documentation of 'git log -L' explicitly told you not to do so
> ("You may not give any pathspec limiters."). This should have
> errored out since the beginning, but, unfortunately, has never
> been enforced.
>
> - Don't use '-L' with '--follow'. On one hand, line-level log on
> its own already follows file renames, even multiple files at once,
> there is no need for an additional '--follow' (which can only
> follow one file). OTOH, you shouldn't be able to use '-L' and
> '--follow' together, because the former forbids a pathspec, while
> the latter requires one.
>
> In any case, '--follow' has always been an ugly hack on top of the
> revision walking machinery, while line-level log is a rather poorly
> integrated bolt-on. They simply weren't designed to work together, as
> evidenced by their contradicting requirements about the pathspec.
This kind of explains issue with --follow and --full-diff which I've reported
recently and got completely ignored.
Are there any plans to integrate --follow better with other tools?
>
>> It occurs because `opt->pathspec.items` gets cleaned here:
>> clear_pathspec
>> queue_diffs
>> /* must look at the full tree diff to detect renames */
>> clear_pathspec(&opt->pathspec);
>> DIFF_QUEUE_CLEAR(&diff_queued_diff);
>> process_ranges_ordinary_commit
>> process_ranges_arbitrary_commit
>> line_log_filter
>> prepare_revision_walk
>> cmd_log_walk
>> cmd_log
>>
>> And on next iteration it crashes in 'try_to_follow_renames' on this line:
>> diff_opts.single_follow = opt->pathspec.items[0].match;
>>
>> I think that bug comes from commit:
>> a2bb801f by SZEDER Gábor, 2019-08-21 13:04:24
>> line-log: avoid unnecessary full tree diffs
>>
>> @szeder could you please look into that?
>>
>> On 27.02.2020 13:56, Ondrej Pohorelsky wrote:
>> >Hi,
>> >
>> >there is a SIGSEGV appearing in Fedora[0] with Git 2.24.1
>> >
>> >This bug started to appear after update to Git 2.24.1.
>> >Bug reporter said that Git crashed on him while running VS Code with
>> >Git Lens extension[1]
>> >I have tried to reproduce this bug with my own compiled Git with debug
>> >flags, but sadly SIGSEGV never appeared.
>> >
>> >To me it seems like there is a problem in commit a2bb801f6a[2] which
>> >changes move_diff_queue() function. This function calls
>> >diff_tree_oid() that calls try_to_follow_renames(). In the last two
>> >functions there are no arguments checks.
>> >
>> >Best regards,
>> >Ondřej Pohořelský
>> >
>> >[0] https://retrace.fedoraproject.org/faf/problems/bthash/?bth=25aa7d7267ab5de548ffca337115cb68f7b65105
>> >[1] https://bugzilla.redhat.com/show_bug.cgi?id=1791810
>> >[2] https://git.kernel.org/pub/scm/git/git.git/commit/?id=a2bb801f6a430f6049e5c9729a8f3bf9097d9b34
>> >
--
Regards,
Konstantin
next prev parent reply other threads:[~2020-03-10 17:30 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-27 12:56 git-core: try_to_follow_renames(): git killed by SIGSEGV Ondrej Pohorelsky
2020-03-06 14:44 ` Alexandr Miloslavskiy
2020-03-10 12:07 ` Ondrej Pohorelsky
2020-03-10 16:57 ` SZEDER Gábor
2020-03-10 17:30 ` Konstantin Tokarev [this message]
2020-03-10 17:35 ` Alexandr Miloslavskiy
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