[PATCH] perf: free original memory on realloc failure in str_append

[David Ahern <dsahern@gmail.com>]

str_append was added in 578d9c6. If realloc fails orignal block is
not freed. Need to save the original pointer to handle on failure.

Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Andi Kleen <ak@linux.intel.com>
---
 tools/perf/util/string.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/string.c b/tools/perf/util/string.c
index f0b0c00..53bca50 100644
--- a/tools/perf/util/string.c
+++ b/tools/perf/util/string.c
@@ -398,13 +398,20 @@ int str_append(char **s, int *len, const char *a)
 {
 	int olen = *s ? strlen(*s) : 0;
 	int nlen = olen + strlen(a) + 1;
+	char *p;
+
 	if (*len < nlen) {
 		*len = *len * 2;
 		if (*len < nlen)
 			*len = nlen;
+
+		p = *s;
 		*s = realloc(*s, *len);
-		if (!*s)
+		if (!*s) {
+			free(p);
 			return -ENOMEM;
+		}
+
 		if (olen == 0)
 			**s = 0;
 	}
-- 
1.7.10.1