linux-kernel - [PATCH AUTOSEL 4.4 69/71] perf parse: Fix potential memory leak when handling tracepoint errors

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Message-Id: <20191210223316.14988-69-sashal@kernel.org>
Date:   Tue, 10 Dec 2019 17:33:14 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Ian Rogers <irogers@...gle.com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Jin Yao <yao.jin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Namhyung Kim <namhyung@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Stephane Eranian <eranian@...gle.com>,
        clang-built-linux@...glegroups.com,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.4 69/71] perf parse: Fix potential memory leak when handling tracepoint errors

From: Ian Rogers <irogers@...gle.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@...gle.com>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Andi Kleen <ak@...ux.intel.com>
Cc: Jin Yao <yao.jin@...ux.intel.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Stephane Eranian <eranian@...gle.com>
Cc: clang-built-linux@...glegroups.com
Link: http://lore.kernel.org/lkml/20191120180925.21787-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.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 9351738df7039..004f28a041238 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -398,6 +398,7 @@ int parse_events_add_cache(struct list_head *list, int *idx,
 static void tracepoint_error(struct parse_events_error *e, int err,
 			     char *sys, char *name)
 {
+	const char *str;
 	char help[BUFSIZ];
 
 	if (!e)
@@ -411,18 +412,18 @@ 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