From: Jeff King <peff@peff.net>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: git@vger.kernel.org, Junio C Hamano <gitster@pobox.com>
Subject: Re: [PATCH 6/6] revisions API: don't leak memory on argv elements that need free()-ing
Date: Fri, 29 Jul 2022 14:37:59 -0400 [thread overview]
Message-ID: <YuQpBwUt8rAE9oym@coredump.intra.peff.net> (raw)
In-Reply-To: <YuQg5M/cSLtqOgdw@coredump.intra.peff.net>
On Fri, Jul 29, 2022 at 02:03:16PM -0400, Jeff King wrote:
> On Fri, Jul 29, 2022 at 09:07:40AM +0200, Ævar Arnfjörð Bjarmason wrote:
>
> > > In that case, we could replace your patch 5 in favor of just calling
> > > strvec_clear() at the end of bisect_rev_setup().
> >
> > 5/6 is doing that, or rather at the end of check_ancestors() and
> > bisect_next_all(), but those call bisect_rev_setup() and pass it the
> > strvec, so in terms of memory management it amounts to the same thing.
>
> Right, but my point is that we do not need to complicate the interface
> and ownership rules for bisect_rev_setup() by passing around the extra
> variable.
Just to be clear, what I'm proposing is to replace your 5/6 with the
patch below.
It passes the leak-checker, but I don't think that should be a surprise.
The end result should be the same as your patch, and anyway I don't
think your series actually marks any scripts as PASSING_SANITIZE_LEAK
as a result of fixing this (presumably because there are other leaks in
those scripts, too).
The more interesting question is whether it causes any use-after-free
bugs. I don't think it does, and certainly SANITIZE=address agrees.
-- >8 --
Subject: [PATCH] bisect: stop leaking strvec in bisect_rev_setup()
Back when 8a534b6124 (bisect: use argv_array API, 2011-09-13) was
written, it was not safe to free the argv we had passed to
setup_revisions() until the actual traversal was done.
But since then, we've had many cleanups that makes this safe; e.g.,
df835d3a0c (add_rev_cmdline(): make a copy of the name argument,
2013-05-25) and 31faeb2088 (object_array_entry: fix memory handling of
the name field, 2013-05-25). The comment here is now out-dated; we can
just clear the strvec rather than leaking.
Note that there's still a small leak because of the way
setup_revisions() handles removed elements internally. That will be
fixed in a subsequent patch.
Signed-off-by: Jeff King <peff@peff.net>
---
bisect.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/bisect.c b/bisect.c
index 421470bfa5..9cce23e929 100644
--- a/bisect.c
+++ b/bisect.c
@@ -670,7 +670,7 @@ static void bisect_rev_setup(struct repository *r, struct rev_info *revs,
read_bisect_paths(&rev_argv);
setup_revisions(rev_argv.nr, rev_argv.v, revs, NULL);
- /* XXX leak rev_argv, as "revs" may still be pointing to it */
+ strvec_clear(&rev_argv);
}
static void bisect_common(struct rev_info *revs)
--
2.37.1.804.g1775fa20e0
next prev parent reply other threads:[~2022-07-29 18:38 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 [this message]
2022-07-29 18:52 ` Junio C Hamano
2022-07-29 19:04 ` Jeff King
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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