* [PATCH v2] perf stat-display: Check if snprintf()'s fmt argument is NULL
@ 2023-08-04 2:09 Kaige Ye
2023-08-14 20:24 ` Ian Rogers
0 siblings, 1 reply; 3+ messages in thread
From: Kaige Ye @ 2023-08-04 2:09 UTC (permalink / raw)
To: peterz, mingo, acme, mark.rutland, alexander.shishkin, jolsa,
namhyung, irogers, adrian.hunter
Cc: linux-perf-users, linux-kernel, Kaige Ye
It is undefined behavior to pass NULL as snprintf()'s fmt argument.
Here is an example to trigger the problem:
$ perf stat --metric-only -x, -e instructions -- sleep 1
insn per cycle,
Segmentation fault (core dumped)
With this patch:
$ perf stat --metric-only -x, -e instructions -- sleep 1
insn per cycle,
,
Signed-off-by: Kaige Ye <ye@kaige.org>
---
V1 -> V2: Addressed Ian's comments (Ian Rogers)
---
tools/perf/util/stat-display.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
index 7329b3340..031888545 100644
--- a/tools/perf/util/stat-display.c
+++ b/tools/perf/util/stat-display.c
@@ -578,7 +578,7 @@ static void print_metric_only_csv(struct perf_stat_config *config __maybe_unused
if (!valid_only_metric(unit))
return;
unit = fixunit(tbuf, os->evsel, unit);
- snprintf(buf, sizeof buf, fmt, val);
+ snprintf(buf, sizeof(buf), fmt ?: "", val);
ends = vals = skip_spaces(buf);
while (isdigit(*ends) || *ends == '.')
ends++;
@@ -600,7 +600,7 @@ static void print_metric_only_json(struct perf_stat_config *config __maybe_unuse
if (!valid_only_metric(unit))
return;
unit = fixunit(tbuf, os->evsel, unit);
- snprintf(buf, sizeof(buf), fmt, val);
+ snprintf(buf, sizeof(buf), fmt ?: "", val);
ends = vals = skip_spaces(buf);
while (isdigit(*ends) || *ends == '.')
ends++;
base-commit: f6b8436bede3e80226e8b2100279c4450c73806a
--
2.41.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] perf stat-display: Check if snprintf()'s fmt argument is NULL
2023-08-04 2:09 [PATCH v2] perf stat-display: Check if snprintf()'s fmt argument is NULL Kaige Ye
@ 2023-08-14 20:24 ` Ian Rogers
2023-08-21 13:54 ` Arnaldo Carvalho de Melo
0 siblings, 1 reply; 3+ messages in thread
From: Ian Rogers @ 2023-08-14 20:24 UTC (permalink / raw)
To: Kaige Ye
Cc: peterz, mingo, acme, mark.rutland, alexander.shishkin, jolsa,
namhyung, adrian.hunter, linux-perf-users, linux-kernel
On Thu, Aug 3, 2023 at 7:10 PM Kaige Ye <ye@kaige.org> wrote:
>
> It is undefined behavior to pass NULL as snprintf()'s fmt argument.
> Here is an example to trigger the problem:
>
> $ perf stat --metric-only -x, -e instructions -- sleep 1
> insn per cycle,
> Segmentation fault (core dumped)
>
> With this patch:
>
> $ perf stat --metric-only -x, -e instructions -- sleep 1
> insn per cycle,
> ,
>
> Signed-off-by: Kaige Ye <ye@kaige.org>
Thanks Kaige!
Reviewed-by: Ian Rogers <irogers@google.com>
> ---
> V1 -> V2: Addressed Ian's comments (Ian Rogers)
> ---
> tools/perf/util/stat-display.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> index 7329b3340..031888545 100644
> --- a/tools/perf/util/stat-display.c
> +++ b/tools/perf/util/stat-display.c
> @@ -578,7 +578,7 @@ static void print_metric_only_csv(struct perf_stat_config *config __maybe_unused
> if (!valid_only_metric(unit))
> return;
> unit = fixunit(tbuf, os->evsel, unit);
> - snprintf(buf, sizeof buf, fmt, val);
> + snprintf(buf, sizeof(buf), fmt ?: "", val);
> ends = vals = skip_spaces(buf);
> while (isdigit(*ends) || *ends == '.')
> ends++;
> @@ -600,7 +600,7 @@ static void print_metric_only_json(struct perf_stat_config *config __maybe_unuse
> if (!valid_only_metric(unit))
> return;
> unit = fixunit(tbuf, os->evsel, unit);
> - snprintf(buf, sizeof(buf), fmt, val);
> + snprintf(buf, sizeof(buf), fmt ?: "", val);
> ends = vals = skip_spaces(buf);
> while (isdigit(*ends) || *ends == '.')
> ends++;
>
> base-commit: f6b8436bede3e80226e8b2100279c4450c73806a
> --
> 2.41.0
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] perf stat-display: Check if snprintf()'s fmt argument is NULL
2023-08-14 20:24 ` Ian Rogers
@ 2023-08-21 13:54 ` Arnaldo Carvalho de Melo
0 siblings, 0 replies; 3+ messages in thread
From: Arnaldo Carvalho de Melo @ 2023-08-21 13:54 UTC (permalink / raw)
To: Ian Rogers
Cc: Kaige Ye, peterz, mingo, mark.rutland, alexander.shishkin, jolsa,
namhyung, adrian.hunter, linux-perf-users, linux-kernel
Em Mon, Aug 14, 2023 at 01:24:06PM -0700, Ian Rogers escreveu:
> On Thu, Aug 3, 2023 at 7:10 PM Kaige Ye <ye@kaige.org> wrote:
> >
> > It is undefined behavior to pass NULL as snprintf()'s fmt argument.
> > Here is an example to trigger the problem:
> >
> > $ perf stat --metric-only -x, -e instructions -- sleep 1
> > insn per cycle,
> > Segmentation fault (core dumped)
> >
> > With this patch:
> >
> > $ perf stat --metric-only -x, -e instructions -- sleep 1
> > insn per cycle,
> > ,
> >
> > Signed-off-by: Kaige Ye <ye@kaige.org>
>
> Thanks Kaige!
>
> Reviewed-by: Ian Rogers <irogers@google.com>
Thanks, applied.
- Arnaldo
> > ---
> > V1 -> V2: Addressed Ian's comments (Ian Rogers)
> > ---
> > tools/perf/util/stat-display.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> > index 7329b3340..031888545 100644
> > --- a/tools/perf/util/stat-display.c
> > +++ b/tools/perf/util/stat-display.c
> > @@ -578,7 +578,7 @@ static void print_metric_only_csv(struct perf_stat_config *config __maybe_unused
> > if (!valid_only_metric(unit))
> > return;
> > unit = fixunit(tbuf, os->evsel, unit);
> > - snprintf(buf, sizeof buf, fmt, val);
> > + snprintf(buf, sizeof(buf), fmt ?: "", val);
> > ends = vals = skip_spaces(buf);
> > while (isdigit(*ends) || *ends == '.')
> > ends++;
> > @@ -600,7 +600,7 @@ static void print_metric_only_json(struct perf_stat_config *config __maybe_unuse
> > if (!valid_only_metric(unit))
> > return;
> > unit = fixunit(tbuf, os->evsel, unit);
> > - snprintf(buf, sizeof(buf), fmt, val);
> > + snprintf(buf, sizeof(buf), fmt ?: "", val);
> > ends = vals = skip_spaces(buf);
> > while (isdigit(*ends) || *ends == '.')
> > ends++;
> >
> > base-commit: f6b8436bede3e80226e8b2100279c4450c73806a
> > --
> > 2.41.0
> >
--
- Arnaldo
^ permalink raw reply [flat|nested] 3+ messages in thread
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2023-08-04 2:09 [PATCH v2] perf stat-display: Check if snprintf()'s fmt argument is NULL Kaige Ye
2023-08-14 20:24 ` Ian Rogers
2023-08-21 13:54 ` Arnaldo Carvalho de Melo
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