[tip:core/urgent] objtool: Fix seg fault caused by missing parameter

[tip-bot for Simon Ser]

Commit-ID:  d89e426499cf36b96161bd32970d6783f1fbcb0e
Gitweb:     https://git.kernel.org/tip/d89e426499cf36b96161bd32970d6783f1fbcb0e
Author:     Simon Ser <contact@xxxxxxxxxxx>
AuthorDate: Sat, 30 Dec 2017 14:43:31 -0600
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sat, 30 Dec 2017 22:04:17 +0100

objtool: Fix seg fault caused by missing parameter

Fix a seg fault when no parameter is provided to 'objtool orc'.

Signed-off-by: Simon Ser <contact@xxxxxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/9172803ec7ebb72535bcd0b7f966ae96d515968e.1514666459.git.jpoimboe@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 tools/objtool/builtin-orc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/objtool/builtin-orc.c b/tools/objtool/builtin-orc.c
index 4c6b5c9..91e8e19 100644
--- a/tools/objtool/builtin-orc.c
+++ b/tools/objtool/builtin-orc.c
@@ -44,6 +44,9 @@ int cmd_orc(int argc, const char **argv)
 	const char *objname;
 
 	argc--; argv++;
+	if (argc <= 0)
+		usage_with_options(orc_usage, check_options);
+
 	if (!strncmp(argv[0], "gen", 3)) {
 		argc = parse_options(argc, argv, check_options, orc_usage, 0);
 		if (argc != 1)
@@ -52,7 +55,6 @@ int cmd_orc(int argc, const char **argv)
 		objname = argv[0];
 
 		return check(objname, no_fp, no_unreachable, true);
-
 	}
 
 	if (!strcmp(argv[0], "dump")) {