[PATCH] selftests/run_kselftest.sh: fix infinite loop on missing argument

[Fernando Fernandez Mancera <fmancera@suse.de>]

Currently, passing an option that requires an argument as the final
parameter without providing the actual argument causes the script to
enter an infinite loop.

Handle this by adding a proper check for the number of positional
parameters.

Signed-off-by: Fernando Fernandez Mancera <fmancera@suse.de>
---
Note: I hit this while automating some testing, I wasted a couple of
hours of CPU cycles + energy
---
 tools/testing/selftests/run_kselftest.sh | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/tools/testing/selftests/run_kselftest.sh b/tools/testing/selftests/run_kselftest.sh
index 84d45254675c..2755c6aa367b 100755
--- a/tools/testing/selftests/run_kselftest.sh
+++ b/tools/testing/selftests/run_kselftest.sh
@@ -58,12 +58,24 @@ while true; do
 			per_test_logging=1
 			shift ;;
 		-t | --test)
+			if [ $# -lt 2 ]; then
+				echo "Error: option '$1' requires an argument" >&2
+				usage 1
+			fi
 			TESTS="$TESTS $2"
 			shift 2 ;;
 		-S | --skip)
+			if [ $# -lt 2 ]; then
+				echo "Error: option '$1' requires an argument" >&2
+				usage 1
+			fi
 			SKIP="$SKIP $2"
 			shift 2 ;;
 		-c | --collection)
+			if [ $# -lt 2 ]; then
+				echo "Error: option '$1' requires an argument" >&2
+				usage 1
+			fi
 			COLLECTIONS="$COLLECTIONS $2"
 			shift 2 ;;
 		-l | --list)
@@ -79,6 +91,10 @@ while true; do
 			RUN_IN_NETNS=1
 			shift ;;
 		-o | --override-timeout)
+			if [ $# -lt 2 ]; then
+				echo "Error: option '$1' requires an argument" >&2
+				usage 1
+			fi
 			kselftest_override_timeout="$2"
 			shift 2 ;;
 		-h | --help)
-- 
2.53.0