+ selftests-mm-fix-assumption-that-sudo-is-present.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: selftests/mm: fix assumption that sudo is present
has been added to the -mm mm-unstable branch.  Its filename is
     selftests-mm-fix-assumption-that-sudo-is-present.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-fix-assumption-that-sudo-is-present.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Brendan Jackman <jackmanb@google.com>
Subject: selftests/mm: fix assumption that sudo is present
Date: Fri, 21 Feb 2025 18:25:41 +0000

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>
---

 tools/testing/selftests/mm/run_vmtests.sh |   22 ++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

--- a/tools/testing/selftests/mm/run_vmtests.sh~selftests-mm-fix-assumption-that-sudo-is-present
+++ a/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-p
 # 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
_

Patches currently in -mm which might be from jackmanb@google.com are

mm-mmu_gather-update-comment-on-rcu-freeing.patch
selftests-mm-report-errno-when-things-fail-in-gup_longterm.patch
selftests-mm-fix-assumption-that-sudo-is-present.patch
selftests-mm-skip-uffd-stress-if-userfaultfd-not-available.patch
selftests-mm-skip-uffd-wp-mremap-if-userfaultfd-not-available.patch
selftests-mm-uffd-rename-nr_cpus-nr_threads.patch
selftests-mm-print-some-details-when-uffd-stress-gets-bad-params.patch
selftests-mm-dont-fail-uffd-stress-if-too-many-cpus.patch
selftests-mm-skip-map_populate-on-weird-filesystems.patch
selftests-mm-skip-gup_longerm-tests-on-weird-filesystems.patch