[PATCH v3 1/3] selftests: kselftest: avoid cd - in runner

[Hajime Tazaki <thehajime@gmail.com>]

The kselftest runner currently uses `cd -` to restore its working
directory after running a test.

This is not supported by the minimal BusyBox hush shell used by some
NOMMU targets. Store the original directory explicitly and restore it
with a quoted path instead.

This also avoids printing the directory change performed by `cd -` and
handles paths containing whitespace correctly.

Cc: Shuah Khan <shuah@kernel.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will Drewry <wad@chromium.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Brendan Jackman <brendan.jackman@linux.dev>
Cc: Hangbin Liu <liuhangbin@gmail.com>
Cc: "Ricardo B. Marliere" <rbm@suse.com>
Cc: linux-kselftest@vger.kernel.org
Cc: linux-um@lists.infradead.org
Cc: linux-mm@kvack.org
Signed-off-by: Hajime Tazaki <thehajime@gmail.com>
---
 tools/testing/selftests/kselftest/runner.sh | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kselftest/runner.sh b/tools/testing/selftests/kselftest/runner.sh
index 311811dc55a0..8fc1018d6fec 100644
--- a/tools/testing/selftests/kselftest/runner.sh
+++ b/tools/testing/selftests/kselftest/runner.sh
@@ -130,6 +130,7 @@ run_one()
 				return $KSFT_FAIL
 			fi
 		fi
+		OLDDIR=$(pwd)
 		cd `dirname $TEST` > /dev/null
 		(((( tap_timeout "$cmd" 2>&1; echo $? >&3) |
 			tap_prefix >&4) 3>&1) |
@@ -147,7 +148,7 @@ run_one()
 		*)
 			ktap_test_fail "$TEST_HDR_MSG # exit=$rc";;
 		esac
-		cd - >/dev/null
+		cd "$OLDDIR" >/dev/null
 	fi
 
 	return $rc
-- 
2.43.0