[RFC] perf: Prevent potential null dereference

[Cyrill Gorcunov <gorcunov@gmail.com>]

In case if there is no memory we might hit null
dereference on accessing calloc'ed data.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
CC: Arnaldo Carvalho de Melo <acme@redhat.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Ingo Molnar <mingo@elte.hu>
CC: Frederic Weisbecker <fweisbec@gmail.com>
---

It seems exit right here is more convenient than passing error
handling level up (which would have to exit anyway), thought
if handling it "upper" is preferred -- just say a word.

 tools/perf/builtin-record.c |    4 ++++
 1 file changed, 4 insertions(+)

Index: linux-2.6.git/tools/perf/builtin-record.c
=====================================================================
--- linux-2.6.git.orig/tools/perf/builtin-record.c
+++ linux-2.6.git/tools/perf/builtin-record.c
@@ -524,6 +524,10 @@ static void comm__construct(int argc, co
 		return;
 
 	comm = calloc(1, size);
+	if (!comm) {
+		pr_err("Not enough memory to construct internal command line.\n");
+		exit(-1);
+	}
 
 	tmp = comm;
 	for (i = 0; i < argc; i++) {