linux-kernel - [PATCH] Lower the ptrace permissions so that the memfd_secrect test program runs without an issue.

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Date:   Mon, 30 Oct 2023 17:54:45 +0900
From:   Itaru Kitayama <itaru.kitayama@...ux.dev>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Shuah Khan <shuah@...nel.org>
Cc:     linux-mm@...ck.org, linux-kselftest@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Itaru Kitayama <itaru.kitayama@...ux.dev>
Subject: [PATCH] Lower the ptrace permissions so that the memfd_secrect
 test program runs without an issue.



---
On Ubuntu and probably other distros, ptrace permissions are tightend a
bit by default; i.e., /proc/sys/kernel/yama/ptrace_score is set to 1.
This cases memfd_secret's ptrace attach test fails with a permission
error. Set it to 0 piror to running the program. 

Signed-off-by: Itaru Kitayama <itaru.kitayama@...ux.dev>
---
 tools/testing/selftests/mm/run_vmtests.sh | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh
index 3e2bc818d566..7d31718ce834 100755
--- a/tools/testing/selftests/mm/run_vmtests.sh
+++ b/tools/testing/selftests/mm/run_vmtests.sh
@@ -303,6 +303,7 @@ CATEGORY="hmm" run_test bash ./test_hmm.sh smoke
 # MADV_POPULATE_READ and MADV_POPULATE_WRITE tests
 CATEGORY="madv_populate" run_test ./madv_populate
 
+echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope
 CATEGORY="memfd_secret" run_test ./memfd_secret
 
 # KSM KSM_MERGE_TIME_HUGE_PAGES test with size of 100

---
base-commit: ffc253263a1375a65fa6c9f62a893e9767fbebfa
change-id: 20231030-selftest-c75b1b460817

Best regards,
-- 
Itaru Kitayama <itaru.kitayama@...ux.dev>