diff --git a/exec_cmd.c b/exec_cmd.c
index e508f1e66d..f8f416b646 100644
--- a/exec_cmd.c
+++ b/exec_cmd.c
@@ -22,7 +22,11 @@ const char *system_path(const char *path)
 
 const char *git_extract_argv0_path(const char *argv0)
 {
-	const char *slash = argv0 + strlen(argv0);
+	const char *slash;
+
+	if (!argv0 || !*argv0)
+		return NULL;
+	slash = argv0 + strlen(argv0);
 
 	while (argv0 <= slash && !is_dir_sep(*slash))
 		slash--;
diff --git a/git.c b/git.c
index bf21e21cef..320cb43564 100644
--- a/git.c
+++ b/git.c
@@ -444,9 +444,8 @@ int main(int argc, const char **argv)
 {
 	const char *cmd;
 
-	if (argv[0] && *argv[0])
-		cmd = git_extract_argv0_path(argv[0]);
-	else
+	cmd = git_extract_argv0_path(argv[0]);
+	if (!cmd)
 		cmd = "git-help";
 
 	/*