From: Brendan Jackman <jackmanb@google.com>
Date: Fri, 21 Feb 2025 18:25:41 +0000 (+0000)
Subject: selftests/mm: fix assumption that sudo is present
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=ef5a5b91dbda9841c5a4b8c6b4304894b589e67d;p=users%2Fjedix%2Flinux-maple.git

selftests/mm: fix assumption that sudo is present

If we are root, sudo isn't needed.  If we are not root, we need sudo, so
skip the test if it isn't present.

We already do this for on-fault-limit, but this uses separate
infrastructure since that is specifically for sudo-ing to the nobody user.

Note this ptrace_skip configuration still fails if that file doesn't
exist, but in that case the test is still fine, so this just prints an
error but doesn't break anything.  I suspect that's probably deliberate.

Link: https://lkml.kernel.org/r/20250221-mm-selftests-v2-2-28c4d66383c5@google.com
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
index d3866b50a6e1..fe3606de37f9 100755
--- a/tools/testing/selftests/mm/run_vmtests.sh
+++ b/tools/testing/selftests/mm/run_vmtests.sh
@@ -89,6 +89,17 @@ RUN_ALL=false
 RUN_DESTRUCTIVE=false
 TAP_PREFIX="# "
 
+# We can do stuff as root either if we are already root, or if sudo exists.
+if [ "$(id -u)" == 0 ]; then
+	HAVE_SUDO_ROOT=true
+	SUDO_ROOT=
+elif command -v sudo >/dev/null 2>&1; then
+	HAVE_SUDO_ROOT=true
+	SUDO_ROOT=sudo
+else
+	HAVE_SUDO_ROOT=false
+fi
+
 while getopts "aht:n" OPT; do
 	case ${OPT} in
 		"a") RUN_ALL=true ;;
@@ -398,10 +409,13 @@ CATEGORY="madv_guard" run_test ./guard-pages
 # MADV_POPULATE_READ and MADV_POPULATE_WRITE tests
 CATEGORY="madv_populate" run_test ./madv_populate
 
-if [ -x ./memfd_secret ]
-then
-(echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope 2>&1) | tap_prefix
-CATEGORY="memfd_secret" run_test ./memfd_secret
+if [ -x ./memfd_secret ]; then
+	if $HAVE_SUDO_ROOT; then
+		(echo 0 | $SUDO_ROOT tee /proc/sys/kernel/yama/ptrace_scope 2>&1) | tap_prefix
+		CATEGORY="memfd_secret" run_test ./memfd_secret
+	else
+		echo "# SKIP ./memfd_secret"
+	fi
 fi
 
 # KSM KSM_MERGE_TIME_HUGE_PAGES test with size of 100