2024-02-23 22:05:44

by Ilkka Koskinen

[permalink] [raw]
Subject: [PATCH v4] perf data convert: Fix segfault when converting to json when cpu_desc isn't set

Arm64 doesn't have Model in /proc/cpuinfo and, thus, cpu_desc doesn't get
assigned.

Running
$ perf data convert --to-json perf.data.json

ends up calling output_json_string() with NULL pointer, which causes a
segmentation fault.

Signed-off-by: Ilkka Koskinen <[email protected]>
---

v1:
- https://lore.kernel.org/all/[email protected]/
v2:
- Changed the patch based on James's comments.
v3:
- The architecture is checked from the actual data file to allow one to do
conversion on another system. (thanks to James for the feedback)
- https://lore.kernel.org/all/[email protected]/
v4:
- Made the fix more generic in case there are other architectures where cpu_desc
isn't assigned as asked by Namhyung
- Rephrased the subject line
---

tools/perf/util/data-convert-json.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/data-convert-json.c b/tools/perf/util/data-convert-json.c
index 5bb3c2ba95ca..09d57efd2d9d 100644
--- a/tools/perf/util/data-convert-json.c
+++ b/tools/perf/util/data-convert-json.c
@@ -284,7 +284,9 @@ static void output_headers(struct perf_session *session, struct convert_json *c)
output_json_key_string(out, true, 2, "os-release", header->env.os_release);
output_json_key_string(out, true, 2, "arch", header->env.arch);

- output_json_key_string(out, true, 2, "cpu-desc", header->env.cpu_desc);
+ if (header->env.cpu_desc)
+ output_json_key_string(out, true, 2, "cpu-desc", header->env.cpu_desc);
+
output_json_key_string(out, true, 2, "cpuid", header->env.cpuid);
output_json_key_format(out, true, 2, "nrcpus-online", "%u", header->env.nr_cpus_online);
output_json_key_format(out, true, 2, "nrcpus-avail", "%u", header->env.nr_cpus_avail);
--
2.43.0



2024-02-24 15:49:46

by Arnaldo Carvalho de Melo

[permalink] [raw]
Subject: Re: [PATCH v4] perf data convert: Fix segfault when converting to json when cpu_desc isn't set

On Fri, Feb 23, 2024 at 02:04:58PM -0800, Ilkka Koskinen wrote:
> Arm64 doesn't have Model in /proc/cpuinfo and, thus, cpu_desc doesn't get
> assigned.
>
> Running
> $ perf data convert --to-json perf.data.json
>
> ends up calling output_json_string() with NULL pointer, which causes a
> segmentation fault.
>
> Signed-off-by: Ilkka Koskinen <[email protected]>

Acked-by: Arnaldo Carvalho de Melo <[email protected]>

- Arnaldo

> ---
>
> v1:
> - https://lore.kernel.org/all/[email protected]/
> v2:
> - Changed the patch based on James's comments.
> v3:
> - The architecture is checked from the actual data file to allow one to do
> conversion on another system. (thanks to James for the feedback)
> - https://lore.kernel.org/all/[email protected]/
> v4:
> - Made the fix more generic in case there are other architectures where cpu_desc
> isn't assigned as asked by Namhyung
> - Rephrased the subject line
> ---
>
> tools/perf/util/data-convert-json.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/data-convert-json.c b/tools/perf/util/data-convert-json.c
> index 5bb3c2ba95ca..09d57efd2d9d 100644
> --- a/tools/perf/util/data-convert-json.c
> +++ b/tools/perf/util/data-convert-json.c
> @@ -284,7 +284,9 @@ static void output_headers(struct perf_session *session, struct convert_json *c)
> output_json_key_string(out, true, 2, "os-release", header->env.os_release);
> output_json_key_string(out, true, 2, "arch", header->env.arch);
>
> - output_json_key_string(out, true, 2, "cpu-desc", header->env.cpu_desc);
> + if (header->env.cpu_desc)
> + output_json_key_string(out, true, 2, "cpu-desc", header->env.cpu_desc);
> +
> output_json_key_string(out, true, 2, "cpuid", header->env.cpuid);
> output_json_key_format(out, true, 2, "nrcpus-online", "%u", header->env.nr_cpus_online);
> output_json_key_format(out, true, 2, "nrcpus-avail", "%u", header->env.nr_cpus_avail);
> --
> 2.43.0

2024-02-27 17:29:50

by Namhyung Kim

[permalink] [raw]
Subject: Re: [PATCH v4] perf data convert: Fix segfault when converting to json when cpu_desc isn't set

On Fri, 23 Feb 2024 14:04:58 -0800, Ilkka Koskinen wrote:
> Arm64 doesn't have Model in /proc/cpuinfo and, thus, cpu_desc doesn't get
> assigned.
>
> Running
> $ perf data convert --to-json perf.data.json
>
> ends up calling output_json_string() with NULL pointer, which causes a
> segmentation fault.
>
> [...]

Applied to perf-tools-next, thanks!

Best regards,
--
Namhyung Kim <[email protected]>