From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BD196C4338F for ; Mon, 26 Jul 2021 20:02:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 973DB60F6E for ; Mon, 26 Jul 2021 20:02:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231540AbhGZTVs (ORCPT ); Mon, 26 Jul 2021 15:21:48 -0400 Received: from pb-smtp1.pobox.com ([64.147.108.70]:65435 "EHLO pb-smtp1.pobox.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229646AbhGZTVq (ORCPT ); Mon, 26 Jul 2021 15:21:46 -0400 Received: from pb-smtp1.pobox.com (unknown [127.0.0.1]) by pb-smtp1.pobox.com (Postfix) with ESMTP id 8D1C9D0D99; Mon, 26 Jul 2021 16:02:14 -0400 (EDT) (envelope-from junio@pobox.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; s=sasl; bh=E8wb2DjQUPUXvD8Od4jw/IZX+6vISOJL6oFKac icrZw=; b=rmDadQK/ITMq+2XwjKK1fjh5EHSj0ExXEQrhgNl0X60vOIFgB4CHk4 qWw+M6ZJnGg9Wytogbp3OJb+4ehNRT5xso8heejwpATW86YzMffg9cWDWOZoyXMM EOALkBIOINKe+DF4xK90TnfXdEo/WGa9+d9mEw4KH/rhIPCaYy2rc= Received: from pb-smtp1.nyi.icgroup.com (unknown [127.0.0.1]) by pb-smtp1.pobox.com (Postfix) with ESMTP id 85536D0D98; Mon, 26 Jul 2021 16:02:14 -0400 (EDT) (envelope-from junio@pobox.com) Received: from pobox.com (unknown [35.196.71.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pb-smtp1.pobox.com (Postfix) with ESMTPSA id D6E00D0D97; Mon, 26 Jul 2021 16:02:13 -0400 (EDT) (envelope-from junio@pobox.com) From: Junio C Hamano To: andrzej@ahunt.org Cc: git@vger.kernel.org, phillip.wood123@gmail.com, newren@gmail.com Subject: Re: [PATCH v2 04/12] builtin/for-each-repo: remove unnecessary argv copy to plug leak References: <20210620151204.19260-1-andrzej@ahunt.org> <20210725130830.5145-1-andrzej@ahunt.org> <20210725130830.5145-5-andrzej@ahunt.org> Date: Mon, 26 Jul 2021 13:02:13 -0700 In-Reply-To: <20210725130830.5145-5-andrzej@ahunt.org> (andrzej@ahunt.org's message of "Sun, 25 Jul 2021 15:08:22 +0200") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Pobox-Relay-ID: 5EB84EB8-EE4C-11EB-B774-8B3BC6D8090B-77302942!pb-smtp1.pobox.com Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org andrzej@ahunt.org writes: > From: Andrzej Hunt > > cmd_for_each_repo() copies argv into args (a strvec), which is later > passed into run_command_on_repo(), which in turn copies that strvec onto > the end of child.args. The initial copy is unnecessary (we never modify > args). We therefore choose to just pass argv directly into > run_command_on_repo(), which lets us avoid the copy and fixes the leak. Makes sense. There is no reason to make these copies. > > LSAN output from t0068: > > Direct leak of 192 byte(s) in 1 object(s) allocated from: > #0 0x7f63bd4ab8b0 in realloc (/usr/lib64/libasan.so.4+0xdc8b0) > #1 0x98d7e6 in xrealloc wrapper.c:126 > #2 0x916914 in strvec_push_nodup strvec.c:19 > #3 0x916a6e in strvec_push strvec.c:26 > #4 0x4be4eb in cmd_for_each_repo builtin/for-each-repo.c:49 > #5 0x410dcd in run_builtin git.c:475 > #6 0x410dcd in handle_builtin git.c:729 > #7 0x414087 in run_argv git.c:818 > #8 0x414087 in cmd_main git.c:949 > #9 0x40e9ec in main common-main.c:52 > #10 0x7f63bc9fa349 in __libc_start_main (/lib64/libc.so.6+0x24349) > > Indirect leak of 22 byte(s) in 2 object(s) allocated from: > #0 0x7f63bd445e30 in __interceptor_strdup (/usr/lib64/libasan.so.4+0x76e30) > #1 0x98d698 in xstrdup wrapper.c:29 > #2 0x916a63 in strvec_push strvec.c:26 > #3 0x4be4eb in cmd_for_each_repo builtin/for-each-repo.c:49 > #4 0x410dcd in run_builtin git.c:475 > #5 0x410dcd in handle_builtin git.c:729 > #6 0x414087 in run_argv git.c:818 > #7 0x414087 in cmd_main git.c:949 > #8 0x40e9ec in main common-main.c:52 > #9 0x7f63bc9fa349 in __libc_start_main (/lib64/libc.so.6+0x24349) > > See also discussion about the original implementation below - this code > appears to have evolved from a callback explaining the double-strvec-copy > pattern, but there's no strong reason to keep that now: > https://lore.kernel.org/git/68bbeca5-314b-08ee-ef36-040e3f3814e9@gmail.com/ > > Signed-off-by: Andrzej Hunt > --- > builtin/for-each-repo.c | 14 ++++---------- > 1 file changed, 4 insertions(+), 10 deletions(-) > > diff --git a/builtin/for-each-repo.c b/builtin/for-each-repo.c > index 52be64a437..fd86e5a861 100644 > --- a/builtin/for-each-repo.c > +++ b/builtin/for-each-repo.c > @@ -10,18 +10,16 @@ static const char * const for_each_repo_usage[] = { > NULL > }; > > -static int run_command_on_repo(const char *path, > - void *cbdata) > +static int run_command_on_repo(const char *path, int argc, const char ** argv) > { > int i; > struct child_process child = CHILD_PROCESS_INIT; > - struct strvec *args = (struct strvec *)cbdata; > > child.git_cmd = 1; > strvec_pushl(&child.args, "-C", path, NULL); > > - for (i = 0; i < args->nr; i++) > - strvec_push(&child.args, args->v[i]); > + for (i = 0; i < argc; i++) > + strvec_push(&child.args, argv[i]); > > return run_command(&child); > } > @@ -31,7 +29,6 @@ int cmd_for_each_repo(int argc, const char **argv, const char *prefix) > static const char *config_key = NULL; > int i, result = 0; > const struct string_list *values; > - struct strvec args = STRVEC_INIT; > > const struct option options[] = { > OPT_STRING(0, "config", &config_key, N_("config"), > @@ -45,9 +42,6 @@ int cmd_for_each_repo(int argc, const char **argv, const char *prefix) > if (!config_key) > die(_("missing --config=")); > > - for (i = 0; i < argc; i++) > - strvec_push(&args, argv[i]); > - > values = repo_config_get_value_multi(the_repository, > config_key); > > @@ -59,7 +53,7 @@ int cmd_for_each_repo(int argc, const char **argv, const char *prefix) > return 0; > > for (i = 0; !result && i < values->nr; i++) > - result = run_command_on_repo(values->items[i].string, &args); > + result = run_command_on_repo(values->items[i].string, argc, argv); > > return result; > }