[PATCH v4 11/12] selftests/mm: Skip mlock tests if nobody user can't read it

[Brendan Jackman <jackmanb@google.com>]

If running from a directory that can't be read by unprivileged users,
executing on-fault-test via the nobody user will fail.

The kselftest build does give the file the correct permissions, but
after being installed it might be in a directory without global execute
permissions.

Since the script can't safely fix that, just skip if it happens. Note
that the stderr of the `ls` command is unfiltered meaning the user sees
a "permission denied" error that can help inform them why the test was
skipped.

Signed-off-by: Brendan Jackman <jackmanb@google.com>
---
 tools/testing/selftests/mm/run_vmtests.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
index e86ef8cb37d00e572be8cf0ea9cc8246d4eecd7e..1467594b594c4fb1dceae875fe7616ecc3cd9382 100755
--- a/tools/testing/selftests/mm/run_vmtests.sh
+++ b/tools/testing/selftests/mm/run_vmtests.sh
@@ -337,7 +337,7 @@ echo "$nr_hugepgs" > /proc/sys/vm/nr_hugepages
 
 CATEGORY="compaction" run_test ./compaction_test
 
-if command -v sudo &> /dev/null;
+if command -v sudo &> /dev/null && sudo -u nobody ls ./on-fault-limit >/dev/null;
 then
 	CATEGORY="mlock" run_test sudo -u nobody ./on-fault-limit
 else

-- 
2.49.0.rc0.332.g42c0ae87b1-goog