diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 2f61f54b8940787f9575b590edac5df325e52744..e9618ca312513922a42f0296361ac967060d79b8 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -867,6 +867,7 @@ sub git_commit_info {
 #		    echo "commit $(cut -c 1-12,41-)"
 #		done
 	} elsif ($lines[0] =~ /^fatal: ambiguous argument '$commit': unknown revision or path not in the working tree\./) {
+		$id = undef;
 	} else {
 		$id = substr($lines[0], 0, 12);
 		$desc = substr($lines[0], 41);
@@ -2606,7 +2607,8 @@ sub process {
 			($id, $description) = git_commit_info($orig_commit,
 							      $id, $orig_desc);
 
-			if ($short || $long || $space || $case || ($orig_desc ne $description) || !$hasparens) {
+			if (defined($id) &&
+			   ($short || $long || $space || $case || ($orig_desc ne $description) || !$hasparens)) {
 				ERROR("GIT_COMMIT_ID",
 				      "Please use git commit description style 'commit <12+ chars of sha1> (\"<title line>\")' - ie: '${init_char}ommit $id (\"$description\")'\n" . $herecurr);
 			}