Messages in this thread | | | Date | Fri, 12 Jan 2024 11:35:27 +0000 | Subject | Re: [PATCH] perf data convert: Fix segfault when converting to json on arm64 | From | James Clark <> |
| |
On 11/01/2024 23:29, 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 <ilkka@os.amperecomputing.com> > --- > tools/perf/util/data-convert-json.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/tools/perf/util/data-convert-json.c b/tools/perf/util/data-convert-json.c > index 5bb3c2ba95ca..5d6de1cef546 100644 > --- a/tools/perf/util/data-convert-json.c > +++ b/tools/perf/util/data-convert-json.c > @@ -97,6 +97,11 @@ static void output_json_format(FILE *out, bool comma, int depth, const char *for > static void output_json_key_string(FILE *out, bool comma, int depth, > const char *key, const char *value) > { > + if (!value) { > + pr_info("No value set for key %s\n", key); > + return; > + } > + > output_json_delimiters(out, comma, depth); > output_json_string(out, key); > fputs(": ", out);
It looks like this would hide new errors on any of the other fields that output_json_key_string() is called on. Maybe it would be better to only wrap the call to output cpu_desc with the if? If that's the only one that we think is optional, and even better only do it for arm64.
I mention this because the test for 'perf data convert' only checks for valid json syntax, but not any fields. So we might want to avoid others going missing.
Thanks James
| |