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From:   Arnaldo Carvalho de Melo <acme@kernel.org>
To:     Ingo Molnar <mingo@kernel.org>
Cc:     Clark Williams <williams@redhat.com>, linux-kernel@vger.kernel.org,
        linux-perf-users@vger.kernel.org,
        Benno Evers <bevers@mesosphere.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Krister Johansen <kjlx@templeofstupid.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Arnaldo Carvalho de Melo <acme@redhat.com>
Subject: [PATCH 26/35] perf tools: Check for null when copying nsinfo.
Date:   Wed, 15 Aug 2018 12:06:02 -0300
Message-Id: <20180815150611.32080-27-acme@kernel.org>
In-Reply-To: <20180815150611.32080-1-acme@kernel.org>
References: <20180815150611.32080-1-acme@kernel.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Benno Evers <bevers@mesosphere.com>

The argument to nsinfo__copy() was assumed to be valid, but some code paths
exist that will lead to NULL being passed.

In particular, running 'perf script -D' on a perf.data file containing an
PERF_RECORD_MMAP event associating the '[vdso]' dso with pid 0 earlier in
the event stream will lead to a segfault.

Since all calling code is already checking for a non-null return value,
just return NULL for this case as well.

Signed-off-by: Benno Evers <bevers@mesosphere.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Krister Johansen <kjlx@templeofstupid.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180810133614.9925-1-bevers@mesosphere.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/namespaces.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
index 5be021701f34..cf8bd123cf73 100644
--- a/tools/perf/util/namespaces.c
+++ b/tools/perf/util/namespaces.c
@@ -139,6 +139,9 @@ struct nsinfo *nsinfo__copy(struct nsinfo *nsi)
 {
 	struct nsinfo *nnsi;
 
+	if (nsi == NULL)
+		return NULL;
+
 	nnsi = calloc(1, sizeof(*nnsi));
 	if (nnsi != NULL) {
 		nnsi->pid = nsi->pid;
-- 
2.14.4