perf probe: Avoid calling freeing routine multiple times for same pointer

When perf_add_probe_events() we call cleanup_perf_probe_events() for the
pev pointer it receives, then, as part of handling this failure the main
'perf probe' goes on and calls cleanup_params() and that will again call
cleanup_perf_probe_events()for the same pointer, so just set nevents to
zero when handling the failure of perf_add_probe_events() to avoid the
double free.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-x8qgma4g813z96dvtw9w219q@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 6418782..3d0ffd4 100644 (file)
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -698,6 +698,16 @@ __cmd_probe(int argc, const char **argv)
 
                ret = perf_add_probe_events(params.events, params.nevents);
                if (ret < 0) {
+
+                       /*
+                        * When perf_add_probe_events() fails it calls
+                        * cleanup_perf_probe_events(pevs, npevs), i.e.
+                        * cleanup_perf_probe_events(params.events, params.nevents), which
+                        * will call clear_perf_probe_event(), so set nevents to zero
+                        * to avoid cleanup_params() to call clear_perf_probe_event() again
+                        * on the same pevs.
+                        */
+                       params.nevents = 0;
                        pr_err_with_code("  Error: Failed to add events.", ret);
                        return ret;
                }