Re: [PATCH] perf probe: Fix uninitialized variable

Masami Hiramatsu
2024-12-10T22:55:17Z

Hi,

On Mon, 9 Dec 2024 17:12:21 +0000
James Clark <james.clark@linaro.org> wrote:

> Since the linked fixes: commit, err is returned uninitialized due to the
> removal of "return 0". Initialize err to fix it, and rename err to out
> to avoid confusion because buf is still supposed to be freed in non
> error cases.
>
> This fixes the following intermittent test failure on release builds:
>
> $ perf test "testsuite_probe"
> ...
> -- [ FAIL ] -- perf_probe :: test_invalid_options :: mutually exclusive options :: -L foo -V bar (output regexp parsing)
> Regexp not found: \"Error: switch .+ cannot be used with switch .+\"
> ...
>
> Fixes: 080e47b2a237 ("perf probe: Introduce quotation marks support")
> Signed-off-by: James Clark <james.clark@linaro.org>
> ---
> tools/perf/util/probe-event.c | 20 ++++++++++----------
> 1 file changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index 6d51a4c98ad7..35af6570cf9b 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -1370,7 +1370,7 @@ int parse_line_range_desc(const char *arg, struct line_range *lr)
> {
> char *buf = strdup(arg);
> char *p;
> - int err;
> + int err = 0;

I think only this is required, and others are just cleanups by renaming
err -> out (usually for-next).
But Arnaldo is OK to combine these changes, I'm OK too.

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thank you,

>
> if (!buf)
> return -ENOMEM;
> @@ -1383,20 +1383,20 @@ int parse_line_range_desc(const char *arg, struct line_range *lr)
> if (p == buf) {
> semantic_error("No file/function name in '%s'.\n", p);
> err = -EINVAL;
> - goto err;
> + goto out;
> }
> *(p++) = '\0';
>
> err = parse_line_num(&p, &lr->start, "start line");
> if (err)
> - goto err;
> + goto out;
>
> if (*p == '+' || *p == '-') {
> const char c = *(p++);
>
> err = parse_line_num(&p, &lr->end, "end line");
> if (err)
> - goto err;
> + goto out;
>
> if (c == '+') {
> lr->end += lr->start;
> @@ -1416,11 +1416,11 @@ int parse_line_range_desc(const char *arg, struct line_range *lr)
> if (lr->start > lr->end) {
> semantic_error("Start line must be smaller"
> " than end line.\n");
> - goto err;
> + goto out;
> }
> if (*p != '\0') {
> semantic_error("Tailing with invalid str '%s'.\n", p);
> - goto err;
> + goto out;
> }
> }
>
> @@ -1431,7 +1431,7 @@ int parse_line_range_desc(const char *arg, struct line_range *lr)
> lr->file = strdup_esq(p);
> if (lr->file == NULL) {
> err = -ENOMEM;
> - goto err;
> + goto out;
> }
> }
> if (*buf != '\0')
> @@ -1439,7 +1439,7 @@ int parse_line_range_desc(const char *arg, struct line_range *lr)
> if (!lr->function && !lr->file) {
> semantic_error("Only '@*' is not allowed.\n");
> err = -EINVAL;
> - goto err;
> + goto out;
> }
> } else if (strpbrk_esq(buf, "/."))
> lr->file = strdup_esq(buf);
> @@ -1448,10 +1448,10 @@ int parse_line_range_desc(const char *arg, struct line_range *lr)
> else { /* Invalid name */
> semantic_error("'%s' is not a valid function name.\n", buf);
> err = -EINVAL;
> - goto err;
> + goto out;
> }
>
> -err:
> +out:
> free(buf);
> return err;
> }
> --
> 2.34.1
>

--
Masami Hiramatsu (Google) <mhiramat@kernel.org>