From: SeongJae Park <sj@xxxxxxxxxx> Subject: selftests/damon: test DAMON enabling with empty target_ids case DAMON debugfs didn't check empty targets when starting monitoring, and the issue is fixed with commit b5ca3e83ddb0 ("mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on"). To avoid future regression, this commit adds a test case for that in DAMON selftests. Link: https://lkml.kernel.org/r/20211201150440.1088-9-sj@xxxxxxxxxx Signed-off-by: SeongJae Park <sj@xxxxxxxxxx> Cc: Brendan Higgins <brendanhiggins@xxxxxxxxxx> Cc: Shuah Khan <shuah@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- tools/testing/selftests/damon/debugfs_attrs.sh | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/tools/testing/selftests/damon/debugfs_attrs.sh~selftests-damon-test-damon-enabling-with-empty-target_ids-case +++ a/tools/testing/selftests/damon/debugfs_attrs.sh @@ -94,4 +94,13 @@ test_write_succ "$file" "" "$orig_conten test_content "$file" "$orig_content" "" "empty input written" echo "$orig_content" > "$file" +# Test empty targets case +# ======================= + +orig_target_ids=$(cat "$DBGFS/target_ids") +echo "" > "$DBGFS/target_ids" +orig_monitor_on=$(cat "$DBGFS/monitor_on") +test_write_fail "$DBGFS/monitor_on" "on" "orig_monitor_on" "empty target ids" +echo "$orig_target_ids" > "$DBGFS/target_ids" + echo "PASS" _