[PATCH AUTOSEL 4.14 127/130] perf parse: Fix potential memory leak when handling tracepoint errors

Sasha Levin
2019-12-10T22:06:13Z

From: Ian Rogers <irogers@google.com>

[ Upstream commit 4584f084aa9d8033d5911935837dbee7b082d0e9 ]

An error may be in place when tracepoint_error is called, use
parse_events__handle_error to avoid a memory leak and to capture the
first and last error. Error detected by LLVM's libFuzzer using the
following event:

$ perf stat -e 'msr/event/,f:e'
event syntax error: 'msr/event/,f:e'
\___ can't access trace events

Error: No permissions to read /sys/kernel/debug/tracing/events/f/e
Hint: Try 'sudo mount -o remount,mode=755 /sys/kernel/debug/tracing/'

Initial error:
event syntax error: 'msr/event/,f:e'
\___ no value assigned for term
Run 'perf list' for a list of valid events

Usage: perf stat [<options>] [<command>]

-e, --event <event> event selector. use 'perf list' to list available events

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: clang-built-linux@googlegroups.com
Link: http://lore.kernel.org/lkml/20191120180925.21787-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/util/parse-events.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 096c52f296d77..6a9ae16cd098d 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -451,6 +451,7 @@ int parse_events_add_cache(struct list_head *list, int *idx,
static void tracepoint_error(struct parse_events_error *e, int err,
const char *sys, const char *name)
{
+ const char *str;
char help[BUFSIZ];

if (!e)
@@ -464,18 +465,18 @@ static void tracepoint_error(struct parse_events_error *e, int err,

switch (err) {
case EACCES:
- e->str = strdup("can't access trace events");
+ str = "can't access trace events";
break;
case ENOENT:
- e->str = strdup("unknown tracepoint");
+ str = "unknown tracepoint";
break;
default:
- e->str = strdup("failed to add tracepoint");
+ str = "failed to add tracepoint";
break;
}

tracing_path__strerror_open_tp(err, help, sizeof(help), sys, name);
- e->help = strdup(help);
+ parse_events__handle_error(e, 0, strdup(str), strdup(help));
}

static int add_tracepoint(struct list_head *list, int *idx,
--
2.20.1