cgroups: save space for the terminator

The original code didn't leave enough space for a NULL terminator.  These
strings are copied with strcpy() into fixed length buffers in
cgroup_root_from_opts().

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Serge E. Hallyn <serge@hallyn.com>
Reviewd-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Ben Blum <bblum@andrew.cmu.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/cgroup.c

@@ -1102,7 +1102,7 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
 			if (opts->release_agent)
 				return -EINVAL;
 			opts->release_agent =
-				kstrndup(token + 14, PATH_MAX, GFP_KERNEL);
+				kstrndup(token + 14, PATH_MAX - 1, GFP_KERNEL);
 			if (!opts->release_agent)
 				return -ENOMEM;
 		} else if (!strncmp(token, "name=", 5)) {
@@ -1123,7 +1123,7 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
 			if (opts->name)
 				return -EINVAL;
 			opts->name = kstrndup(name,
-					      MAX_CGROUP_ROOT_NAMELEN,
+					      MAX_CGROUP_ROOT_NAMELEN - 1,
 					      GFP_KERNEL);
 			if (!opts->name)
 				return -ENOMEM;