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Message-ID: <Zz7Kbp_XIu9f02Xj@google.com>
Date: Wed, 20 Nov 2024 21:51:42 -0800
From: Namhyung Kim <namhyung@...nel.org>
To: Ian Rogers <irogers@...gle.com>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
Kan Liang <kan.liang@...ux.intel.com>,
linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1] perf hwmon_pmu: Ensure hwmon key union is zeroed
before use
On Tue, Nov 19, 2024 at 03:00:33PM -0800, Ian Rogers wrote:
> Non-zero values led to mismatches in testing. This was reproducible
> with -fsanitize=undefined.
It's sad the compiler didn't initialize all the members if it has
members with different size.
>
> Reported-by: Arnaldo Carvalho de Melo <acme@...nel.org>
> Closes: https://lore.kernel.org/lkml/Zzdtj0PEWEX3ATwL@x1/
> Signed-off-by: Ian Rogers <irogers@...gle.com>
Acked-by: Namhyung Kim <namhyung@...nel.org>
Thanks,
Namhyung
> ---
> tools/perf/util/hwmon_pmu.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/util/hwmon_pmu.c b/tools/perf/util/hwmon_pmu.c
> index ac2245acdc6d..4d9d6f405434 100644
> --- a/tools/perf/util/hwmon_pmu.c
> +++ b/tools/perf/util/hwmon_pmu.c
> @@ -274,7 +274,7 @@ static int hwmon_pmu__read_events(struct hwmon_pmu *pmu)
> int number;
> enum hwmon_item item;
> bool alarm;
> - union hwmon_pmu_event_key key = {};
> + union hwmon_pmu_event_key key = { .type_and_num = 0 };
> struct hwmon_pmu_event_value *value;
>
> if (ent->d_type != DT_REG)
> @@ -560,7 +560,7 @@ bool hwmon_pmu__have_event(struct perf_pmu *pmu, const char *name)
> struct hwmon_pmu *hwm = container_of(pmu, struct hwmon_pmu, pmu);
> enum hwmon_type type;
> int number;
> - union hwmon_pmu_event_key key = {};
> + union hwmon_pmu_event_key key = { .type_and_num = 0 };
> struct hashmap_entry *cur;
> size_t bkt;
>
> @@ -623,10 +623,11 @@ static int hwmon_pmu__config_term(const struct hwmon_pmu *hwm,
> return -EINVAL;
> } else {
> union hwmon_pmu_event_key key = {
> - .type = type,
> - .num = number,
> + .type_and_num = 0,
> };
>
> + key.type = type;
> + key.num = number;
> attr->config = key.type_and_num;
> }
> return 0;
> --
> 2.47.0.371.ga323438b13-goog
>
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