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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Leo Yan <leo.yan@linaro.org>,
        Jiri Olsa <jolsa@kernel.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Alexey Budankov <alexey.budankov@linux.intel.com>,
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        Andi Kleen <ak@linux.intel.com>,
        Changbin Du <changbin.du@intel.com>,
        "David S. Miller" <davem@davemloft.net>,
        Davidlohr Bueso <dave@stgolabs.net>,
        Eric Saint-Etienne <eric.saint.etienne@oracle.com>,
        Jin Yao <yao.jin@linux.intel.com>,
        Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Song Liu <songliubraving@fb.com>,
        Suzuki Poulouse <suzuki.poulose@arm.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Thomas Richter <tmricht@linux.ibm.com>,
        linux-arm-kernel@lists.infradead.org,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 069/113] perf top: Fix potential NULL pointer dereference detected by the smatch tool
Date:   Mon, 29 Jul 2019 21:22:36 +0200
Message-Id: <20190729190711.996881254@linuxfoundation.org>
In-Reply-To: <20190729190655.455345569@linuxfoundation.org>
References: <20190729190655.455345569@linuxfoundation.org>
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[ Upstream commit 111442cfc8abdeaa7ec1407f07ef7b3e5f76654e ]

Based on the following report from Smatch, fix the potential NULL
pointer dereference check.

  tools/perf/builtin-top.c:109
  perf_top__parse_source() warn: variable dereferenced before check 'he'
  (see line 103)

  tools/perf/builtin-top.c:233
  perf_top__show_details() warn: variable dereferenced before check 'he'
  (see line 228)

  tools/perf/builtin-top.c
  101 static int perf_top__parse_source(struct perf_top *top, struct hist_entry *he)
  102 {
  103         struct perf_evsel *evsel = hists_to_evsel(he->hists);
                                                        ^^^^
  104         struct symbol *sym;
  105         struct annotation *notes;
  106         struct map *map;
  107         int err = -1;
  108
  109         if (!he || !he->ms.sym)
  110                 return -1;

This patch moves the values assignment after validating pointer 'he'.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Alexios Zavras <alexios.zavras@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Changbin Du <changbin.du@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Eric Saint-Etienne <eric.saint.etienne@oracle.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20190702103420.27540-4-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/perf/builtin-top.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 33eefc33e0ea..d0733251a386 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -99,7 +99,7 @@ static void perf_top__resize(struct perf_top *top)
 
 static int perf_top__parse_source(struct perf_top *top, struct hist_entry *he)
 {
-	struct perf_evsel *evsel = hists_to_evsel(he->hists);
+	struct perf_evsel *evsel;
 	struct symbol *sym;
 	struct annotation *notes;
 	struct map *map;
@@ -108,6 +108,8 @@ static int perf_top__parse_source(struct perf_top *top, struct hist_entry *he)
 	if (!he || !he->ms.sym)
 		return -1;
 
+	evsel = hists_to_evsel(he->hists);
+
 	sym = he->ms.sym;
 	map = he->ms.map;
 
@@ -224,7 +226,7 @@ static void perf_top__record_precise_ip(struct perf_top *top,
 static void perf_top__show_details(struct perf_top *top)
 {
 	struct hist_entry *he = top->sym_filter_entry;
-	struct perf_evsel *evsel = hists_to_evsel(he->hists);
+	struct perf_evsel *evsel;
 	struct annotation *notes;
 	struct symbol *symbol;
 	int more;
@@ -232,6 +234,8 @@ static void perf_top__show_details(struct perf_top *top)
 	if (!he)
 		return;
 
+	evsel = hists_to_evsel(he->hists);
+
 	symbol = he->ms.sym;
 	notes = symbol__annotation(symbol);
 
-- 
2.20.1