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Subject[PATCH 1/1] perf probe: Free string returned by synthesize_perf_probe_point() on failure to add a probe
Building perf with EXTRA_CFLAGS="-fsanitize=address" a leak is detect
when trying to add a probe to a non-existent function:

# perf probe -x ~/bin/perf dso__neW
Probe point 'dso__neW' not found.
Error: Failed to add events.

=================================================================
==296634==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 128 byte(s) in 1 object(s) allocated from:
#0 0x7f67642ba097 in calloc (/lib64/libasan.so.8+0xba097)
#1 0x7f67641a76f1 in allocate_cfi (/lib64/libdw.so.1+0x3f6f1)

Direct leak of 65 byte(s) in 1 object(s) allocated from:
#0 0x7f67642b95b5 in __interceptor_realloc.part.0 (/lib64/libasan.so.8+0xb95b5)
#1 0x6cac75 in strbuf_grow util/strbuf.c:64
#2 0x6ca934 in strbuf_init util/strbuf.c:25
#3 0x9337d2 in synthesize_perf_probe_point util/probe-event.c:2018
#4 0x92be51 in try_to_find_probe_trace_events util/probe-event.c:964
#5 0x93d5c6 in convert_to_probe_trace_events util/probe-event.c:3512
#6 0x93d6d5 in convert_perf_probe_events util/probe-event.c:3529
#7 0x56f37f in perf_add_probe_events /var/home/acme/git/perf-tools-next/tools/perf/builtin-probe.c:354
#8 0x572fbc in __cmd_probe /var/home/acme/git/perf-tools-next/tools/perf/builtin-probe.c:738
#9 0x5730f2 in cmd_probe /var/home/acme/git/perf-tools-next/tools/perf/builtin-probe.c:766
#10 0x635d81 in run_builtin /var/home/acme/git/perf-tools-next/tools/perf/perf.c:323
#11 0x6362c1 in handle_internal_command /var/home/acme/git/perf-tools-next/tools/perf/perf.c:377
#12 0x63667a in run_argv /var/home/acme/git/perf-tools-next/tools/perf/perf.c:421
#13 0x636b8d in main /var/home/acme/git/perf-tools-next/tools/perf/perf.c:537
#14 0x7f676302950f in __libc_start_call_main (/lib64/libc.so.6+0x2950f)

SUMMARY: AddressSanitizer: 193 byte(s) leaked in 2 allocation(s).
#

synthesize_perf_probe_point() returns a "detached" strbuf, i.e. a
malloc'ed string that needs to be free'd.

An audit will be performed to find other such cases.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/lkml/
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/probe-event.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 2d056f02ae408a64..c7bfeab610a3679a 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -961,8 +961,9 @@ static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
debuginfo__delete(dinfo);

if (ntevs == 0) { /* No error but failed to find probe point. */
- pr_warning("Probe point '%s' not found.\n",
- synthesize_perf_probe_point(&pev->point));
+ char *probe_point = synthesize_perf_probe_point(&pev->point);
+ pr_warning("Probe point '%s' not found.\n", probe_point);
+ free(probe_point);
return -ENODEV;
} else if (ntevs < 0) {
/* Error path : ntevs < 0 */
--
2.37.1
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