Re: [PATCH v2 2/4] SANITIZE tests: fix memory leaks in t13*config*, add to whitelist
- From
Andrzej Hunt <andrzej@ahunt.org>
- Date
- Jul 14, 2021, 18:57 UTC
- Message-ID
- <871ea493-e108-e748-0234-f929690ad2fd@ahunt.org>
- In-Reply-To
- <patch-2.4-867e8e9a6c-20210714T172251Z-avarab@gmail.com>
On 14/07/2021 19:23, Ævar Arnfjörð Bjarmason wrote:
Show 73 quoted lines
> Fix a couple of trivial memory leaks introduced in 3efd0bedc6 (config:
> add conditional include, 2017-03-01) and my own 867ad08a26 (hooks:
> allow customizing where the hook directory is, 2016-05-04).
>
> In the latter case the "fix" is UNLEAK() on the global variable. This
> allows us to run all t13*config* tests under SANITIZE=leak.
>
> With this change we can now run almost the whole set of config.c
> tests (t13*config) under SANITIZE=leak, so let's do so, with a few
> exceptions:
>
> * The test added in ce81b1da23 (config: add new way to pass config
> via `--config-env`, 2021-01-12), it fails in GitHub CI, but passes
> for me locally. Let's just skip it for now.
>
> * Ditto the split_cmdline and "aliases of builtins" tests, the former
> required splitting up an existing test, there an issue with the test
> that would have also been revealed by skipping it.
>
> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
> config.c | 17 ++++++++++++-----
> t/t1300-config.sh | 16 ++++++++++------
> t/test-lib.sh | 1 +
> 3 files changed, 23 insertions(+), 11 deletions(-)
>
> diff --git a/config.c b/config.c
> index f9c400ad30..38e132c0e2 100644
> --- a/config.c
> +++ b/config.c
> @@ -138,8 +138,10 @@ static int handle_path_include(const char *path, struct config_include_data *inc
> return config_error_nonbool("include.path");
>
> expanded = expand_user_path(path, 0);
> - if (!expanded)
> - return error(_("could not expand include path '%s'"), path);
> + if (!expanded) {
> + ret = error(_("could not expand include path '%s'"), path);
> + goto cleanup;
> + }
> path = expanded;
>
> /*
> @@ -149,8 +151,10 @@ static int handle_path_include(const char *path, struct config_include_data *inc
> if (!is_absolute_path(path)) {
> char *slash;
>
> - if (!cf || !cf->path)
> - return error(_("relative config includes must come from files"));
> + if (!cf || !cf->path) {
> + ret = error(_("relative config includes must come from files"));
> + goto cleanup;
> + }
>
> slash = find_last_dir_sep(cf->path);
> if (slash)
> @@ -168,6 +172,7 @@ static int handle_path_include(const char *path, struct config_include_data *inc
> ret = git_config_from_file(git_config_include, path, inc);
> inc->depth--;
> }
> +cleanup:
> strbuf_release(&buf);
> free(expanded);
> return ret;
> @@ -1331,8 +1336,10 @@ static int git_default_core_config(const char *var, const char *value, void *cb)
> if (!strcmp(var, "core.attributesfile"))
> return git_config_pathname(&git_attributes_file, var, value);
>
> - if (!strcmp(var, "core.hookspath"))
> + if (!strcmp(var, "core.hookspath")) {
> + UNLEAK(git_hooks_path);
> return git_config_pathname(&git_hooks_path, var, value);
> + }Why is the UNLEAK necessary here? We generally want to limit use of UNLEAK to cmd_* functions or direct helpers. git_default_core_config() seems generic enough that it could be called from anywhere, and using UNLEAK here means we're potentially masking a real leak?
IIUC the leak here happens because: - git_hooks_path is a global variable - hence it's unlikely we'd ever bother cleaning it up. - git_default_core_config() gets called a first time with core.hookspath, and we end up allocating new memory into git_hooks_path. - git_default_core_config() gets called again with core.hookspath, and we overwrite git_hooks_path with a new string which leaks the string that git_hooks_path used to point to.
So I think the real fix is to free(git_hooks_path) instead of an UNLEAK? (Looking at the surrounding code, it looks like the same pattern of leak might be repeated for other similar globals - is it worth auditing those while we're here?)
Show 59 quoted lines
>
> if (!strcmp(var, "core.bare")) {
> is_bare_repository_cfg = git_config_bool(var, value);
> diff --git a/t/t1300-config.sh b/t/t1300-config.sh
> index 9ff46f3b04..93ad0f4887 100755
> --- a/t/t1300-config.sh
> +++ b/t/t1300-config.sh
> @@ -1050,12 +1050,16 @@ test_expect_success SYMLINKS 'symlink to nonexistent configuration' '
> test_must_fail git config --file=linktolinktonada --list
> '
>
> -test_expect_success 'check split_cmdline return' "
> - git config alias.split-cmdline-fix 'echo \"' &&
> - test_must_fail git split-cmdline-fix &&
> +test_expect_success 'setup check split_cmdline return' "
> echo foo > foo &&
> git add foo &&
> - git commit -m 'initial commit' &&
> + git commit -m 'initial commit'
> +"
> +
> +test_expect_success !SANITIZE_LEAK 'check split_cmdline return' "
> + git config alias.split-cmdline-fix 'echo \"' &&
> + test_must_fail git split-cmdline-fix &&
> +
> git config branch.main.mergeoptions 'echo \"' &&
> test_must_fail git merge main
> "
> @@ -1101,7 +1105,7 @@ test_expect_success 'key sanity-checking' '
> git config foo."ba =z".bar false
> '
>
> -test_expect_success 'git -c works with aliases of builtins' '
> +test_expect_success !SANITIZE_LEAK 'git -c works with aliases of builtins' '
> git config alias.checkconfig "-c foo.check=bar config foo.check" &&
> echo bar >expect &&
> git checkconfig >actual &&
> @@ -1397,7 +1401,7 @@ test_expect_success 'git --config-env with missing value' '
> grep "invalid config format: config" error
> '
>
> -test_expect_success 'git --config-env fails with invalid parameters' '
> +test_expect_success !SANITIZE_LEAK 'git --config-env fails with invalid parameters' '
> test_must_fail git --config-env=foo.flag config --bool foo.flag 2>error &&
> test_i18ngrep "invalid config format: foo.flag" error &&
> test_must_fail git --config-env=foo.flag= config --bool foo.flag 2>error &&
> diff --git a/t/test-lib.sh b/t/test-lib.sh
> index 9201510e16..98e20950c3 100644
> --- a/t/test-lib.sh
> +++ b/t/test-lib.sh
> @@ -1370,6 +1370,7 @@ maybe_skip_all_sanitize_leak () {
> add_sanitize_leak_true 't000*'
> add_sanitize_leak_true 't001*'
> add_sanitize_leak_true 't006*'
> + add_sanitize_leak_true 't13*config*'
>
> # Blacklist patterns (overrides whitelist)
> add_sanitize_leak_false 't000[469]*'
>