Commit 36d3e413 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo
Browse files

perf script: Fix allocation of evsel->priv related to per-event dump files 



When printing output we may want to generate per event files, where the
--per-event-dump option should be used, creating perf.data.EVENT.dump
files instead of printing to stdout.

The callback thar processes event thus expects that evsel->priv->fp
should point to either the per-event FILE descriptor or to stdout.

The a3af66f5 ("perf script: Fix crash because of missing
evsel->priv") changeset fixed a case where evsel->priv wasn't setup,
thus set to NULL, causing a segfault when trying to access
evsel->priv->fp.

But it did it for the non --per-event-dump case by allocating a 'struct
perf_evsel_script' just to set its ->fp to stdout.

Since evsel->priv is only freed when --per-event-dump is used, we ended
up with a memory leak, detected using ASAN.

Fix it by using the same method as perf_script__setup_per_event_dump(),
and reuse that static 'struct perf_evsel_script'.

Also check if evsel_script__new() failed.

Fixes: a3af66f5 ("perf script: Fix crash because of missing evsel->priv")
Reported-by: default avatarIan Rogers <irogers@google.com>
Tested-by: default avatarIan Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Link: https://lore.kernel.org/lkml/ZH+F0wGAWV14zvMP@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent d6748385

tools/perf/builtin-script.c

+8 −8
Original line number Diff line number Diff line
@@ -2410,6 +2410,9 @@ static int process_sample_event(struct perf_tool *tool, 
	return ret;

}



// Used when scr->per_event_dump is not set

static struct evsel_script es_stdout;



static int process_attr(struct perf_tool *tool, union perf_event *event,

			struct evlist **pevlist)

{
@@ -2418,7 +2421,6 @@ static int process_attr(struct perf_tool *tool, union perf_event *event, 
	struct evsel *evsel, *pos;

	u64 sample_type;

	int err;

	static struct evsel_script *es;



	err = perf_event__process_attr(tool, event, pevlist);

	if (err)
@@ -2430,12 +2432,11 @@ static int process_attr(struct perf_tool *tool, union perf_event *event, 
	if (!evsel->priv) {

		if (scr->per_event_dump) { 

			evsel->priv = evsel_script__new(evsel, scr->session->data);

		} else {

			es = zalloc(sizeof(*es));

			if (!es)

			if (!evsel->priv)

				return -ENOMEM;

			es->fp = stdout;

			evsel->priv = es;

		} else { // Replicate what is done in perf_script__setup_per_event_dump()

			es_stdout.fp = stdout;

			evsel->priv = &es_stdout;

		}

	}
@@ -2741,7 +2742,6 @@ static int perf_script__fopen_per_event_dump(struct perf_script *script) 
static int perf_script__setup_per_event_dump(struct perf_script *script)

{

	struct evsel *evsel;

	static struct evsel_script es_stdout;



	if (script->per_event_dump)

		return perf_script__fopen_per_event_dump(script);