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From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>, git@vger.kernel.org
Subject: Re: [PATCH 6/6] revisions API: don't leak memory on argv elements that need free()-ing
Date: Fri, 29 Jul 2022 15:04:48 -0400	[thread overview]
Message-ID: <YuQvUDlGPTHu2sOm@coredump.intra.peff.net> (raw)
In-Reply-To: <xmqqk07v69bh.fsf@gitster.g>

On Fri, Jul 29, 2022 at 11:52:02AM -0700, Junio C Hamano wrote:

> Jeff King <peff@peff.net> writes:
> 
> > The more interesting question is whether it causes any use-after-free
> > bugs.
> 
> Thanks for mentioning this.  All the "plug more leaks" patches make
> me worried for exactly that.  Another is a potential subtle breakage
> hidden by use of FREE_AND_NULL() and friends, which the sanitizers
> would probably not see, but can appear as behaviour change.

Yeah, agreed that is a potential pitfall.

> > I don't think it does, and certainly SANITIZE=address agrees.
> 
> ;-)

Just to expound a bit: I'm quite sure _this_ call site is fine, because
we are passing pretty vanilla options to setup_revisions(), and I looked
at how we handle the strings there. I'd worry a little more that there's
some dark corner of setup_revisions() which relies on memory lifetimes,
and so this isn't a safe thing to do in the general case.

But IMHO we should assume that setup_revisions() makes copies of strings
it needs, and if there is a dark corner where it doesn't, we should find
and fix that.

-Peff

  reply	other threads:[~2022-07-29 19:06 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-13 13:10 [PATCH 0/6] revisions API: fix more memory leaks Ævar Arnfjörð Bjarmason
2022-07-13 13:10 ` [PATCH 1/6] bisect.c: add missing "goto" for release_revisions() Ævar Arnfjörð Bjarmason
2022-07-13 13:10 ` [PATCH 2/6] test-fast-rebase helper: use release_revisions() (again) Ævar Arnfjörð Bjarmason
2022-07-13 13:10 ` [PATCH 3/6] log: make the intent of cmd_show()'s "rev.pending" juggling clearer Ævar Arnfjörð Bjarmason
2022-07-18 14:51   ` Jeff King
2022-07-13 13:10 ` [PATCH 4/6] log: fix common "rev.pending" memory leak in "git show" Ævar Arnfjörð Bjarmason
2022-07-18 14:57   ` Jeff King
2022-07-18 15:08     ` Ævar Arnfjörð Bjarmason
2022-07-13 13:10 ` [PATCH 5/6] bisect.c: partially fix bisect_rev_setup() memory leak Ævar Arnfjörð Bjarmason
2022-07-18 15:05   ` Jeff King
2022-07-13 13:10 ` [PATCH 6/6] revisions API: don't leak memory on argv elements that need free()-ing Ævar Arnfjörð Bjarmason
2022-07-18 15:11   ` Jeff King
2022-07-18 15:13     ` Ævar Arnfjörð Bjarmason
2022-07-18 15:45       ` Jeff King
2022-07-29  7:07         ` Ævar Arnfjörð Bjarmason
2022-07-29 18:03           ` Jeff King
2022-07-29 18:37             ` Jeff King
2022-07-29 18:52               ` Junio C Hamano
2022-07-29 19:04                 ` Jeff King [this message]
2022-07-18 15:14 ` [PATCH 0/6] revisions API: fix more memory leaks Jeff King
2022-07-29  8:31 ` [PATCH v2 " Ævar Arnfjörð Bjarmason
2022-07-29  8:31   ` [PATCH v2 1/6] bisect.c: add missing "goto" for release_revisions() Ævar Arnfjörð Bjarmason
2022-07-29  8:31   ` [PATCH v2 2/6] test-fast-rebase helper: use release_revisions() (again) Ævar Arnfjörð Bjarmason
2022-07-30  5:22     ` Eric Sunshine
2022-07-29  8:31   ` [PATCH v2 3/6] log: make the intent of cmd_show()'s "rev.pending" juggling clearer Ævar Arnfjörð Bjarmason
2022-07-29 18:44     ` Junio C Hamano
2022-07-29  8:31   ` [PATCH v2 4/6] log: fix common "rev.pending" memory leak in "git show" Ævar Arnfjörð Bjarmason
2022-07-29 18:55     ` Jeff King
2022-07-29 19:07       ` Jeff King
2022-07-29 18:59     ` Jeff King
2022-07-29  8:31   ` [PATCH v2 5/6] bisect.c: partially fix bisect_rev_setup() memory leak Ævar Arnfjörð Bjarmason
2022-07-29  8:31   ` [PATCH v2 6/6] revisions API: don't leak memory on argv elements that need free()-ing Ævar Arnfjörð Bjarmason
2022-07-29 19:00     ` Jeff King
2022-07-29 19:02   ` [PATCH v2 0/6] revisions API: fix more memory leaks Jeff King
2022-08-02 15:33   ` [PATCH v3 " Ævar Arnfjörð Bjarmason
2022-08-02 15:33     ` [PATCH v3 1/6] bisect.c: add missing "goto" for release_revisions() Ævar Arnfjörð Bjarmason
2022-08-03 17:13       ` Junio C Hamano
2022-08-02 15:33     ` [PATCH v3 2/6] test-fast-rebase helper: use release_revisions() (again) Ævar Arnfjörð Bjarmason
2022-08-02 15:33     ` [PATCH v3 3/6] log: fix a memory leak in "git show <revision>..." Ævar Arnfjörð Bjarmason
2022-08-03 17:27       ` Jeff King
2022-08-03 17:29         ` Jeff King
2022-08-03 17:54       ` Junio C Hamano
2022-08-02 15:33     ` [PATCH v3 4/6] log: refactor "rev.pending" code in cmd_show() Ævar Arnfjörð Bjarmason
2022-08-03 17:32       ` Jeff King
2022-08-03 17:59       ` Junio C Hamano
2022-08-04  7:51         ` Ævar Arnfjörð Bjarmason
2022-08-04 15:59           ` Junio C Hamano
2022-08-05  9:01             ` Ævar Arnfjörð Bjarmason
2022-08-02 15:33     ` [PATCH v3 5/6] bisect.c: partially fix bisect_rev_setup() memory leak Ævar Arnfjörð Bjarmason
2022-08-02 15:33     ` [PATCH v3 6/6] revisions API: don't leak memory on argv elements that need free()-ing Ævar Arnfjörð Bjarmason
2022-08-03 18:30       ` Junio C Hamano
2022-08-03 17:33     ` [PATCH v3 0/6] revisions API: fix more memory leaks Jeff King

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