diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index 2b31d5f1f2..585f03681b 100644
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -78,7 +78,9 @@ to exist in the superproject. If <path> is not given, the
 <repository> is the URL of the new submodule's origin repository.
 This may be either an absolute URL, or (if it begins with ./
 or ../), the location relative to the superproject's origin
-repository.
+repository. If the superproject doesn't have an origin configured
+the superproject is its own authoritative upstream and the current
+working directory is used instead.
 +
 <path> is the relative location for the cloned submodule to
 exist in the superproject. If <path> does not exist, then the
diff --git a/git-submodule.sh b/git-submodule.sh
index 20c9bec970..f8ea3bf6f2 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -34,7 +34,7 @@ resolve_relative_url ()
 {
 	remote=$(get_default_remote)
 	remoteurl=$(git config "remote.$remote.url") ||
-		die "remote ($remote) does not have a url defined in .git/config"
+		remoteurl=$(pwd) # the repository is its own authoritative upstream
 	url="$1"
 	remoteurl=${remoteurl%/}
 	sep=/
@@ -238,14 +238,6 @@ cmd_add()
 			die "'$path' already exists and is not a valid git repo"
 		fi
 
-		case "$repo" in
-		./*|../*)
-			url=$(resolve_relative_url "$repo") || exit
-		    ;;
-		*)
-			url="$repo"
-			;;
-		esac
 	else
 
 		module_clone "$path" "$realrepo" "$reference" || exit
@@ -259,7 +251,7 @@ cmd_add()
 			esac
 		) || die "Unable to checkout submodule '$path'"
 	fi
-	git config submodule."$path".url "$url"
+	git config submodule."$path".url "$realrepo"
 
 	git add $force "$path" ||
 	die "Failed to add submodule '$path'"
diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index 3f115d9ca9..662fe91295 100755
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -448,6 +448,16 @@ test_expect_success 'add should fail when path is used by an existing directory'
 	)
 '
 
+test_expect_success 'use superproject as upstream when path is relative and no url is set there' '
+	(
+		cd addtest &&
+		git submodule add ../repo relative &&
+		test "$(git config -f .gitmodules submodule.relative.url)" = ../repo &&
+		git submodule sync relative &&
+		test "$(git config submodule.relative.url)" = "$submodurl/repo"
+	)
+'
+
 test_expect_success 'set up for relative path tests' '
 	mkdir reltest &&
 	(