From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 812B244682A for ; Tue, 11 Aug 2026 14:16:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786457784; cv=none; b=LWF529iMi2ThViS+3LGKpPH07SzSwOCJJamzFGOX+VZdl9PsXKAVS9AhSQkEfR8UFnoifNgKLyJ3rDKDMaRQWE3ahX9AVJKbREsXrNy0dd1yLqfXUG28ecULGaWvnGeINLFRfE9rSryYQ9O8X3DZbDRWWef/FDE2tfc3og549sE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786457784; c=relaxed/simple; bh=wRpqR/zkzI351Zo+QRkwX1SItWGFavuOgid75jSHykU=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=RYm481k2TJGDMvd1xbECBkB77/obVy/ZK9uJRgDb37cGpl9lgSiRlbPVOzdVs9h/HT5NRozqCg4Agl+4cTiMEt0guqhuUXI2in2JefJ2IsGJ805Z1iG2k/ig3YftMtCsnx9AbWZBdU95DiDO28lNiAHi0agR1Ha19UgycqKodG4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PWXZQaD+; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="PWXZQaD+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 42C191F00AC4; Tue, 11 Aug 2026 14:16:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786457782; bh=4xemtyNoA0+DgAam0X5lhttjXqV9do8nY2YtMAqn98s=; h=Date:From:To:Cc:Subject:References; b=PWXZQaD+jbLQmQv1LygxHTHpaqqOwv0EO1uNMBqA+0iQwHYI8EgVXgEyT56kpXCz0 ucreI8iKH5ZfJxcMl4jb5b3uJPnKJ6bPI6I8PLOWPelg20BcaLk3i31Un6PEeaAtea 6gWdLCNR+BEF6CCqHbPda0hsU5l0hMr+H1Kjjv42/eWJU4XQoVcuDtAQnWRqAbA6wm WR9klimXWIMMLVFNCpn/S89wCteLenc8cmmwwmoJDWX5LJE5Sk644BmMbLwS3kZUmo cpAmvb4lDkGjsYygGP5U1kionnNzTo/vPMwSUdLYSwKXF13HRRBoPnWQW9z9TD4kZ7 UE7ntk6KB/8ig== Received: from rostedt by gandalf with local (Exim 4.99.4) (envelope-from ) id 1wtnHO-00000002XXc-0qFa; Tue, 11 Aug 2026 10:16:34 -0400 Message-ID: <20260811141634.056770070@kernel.org> User-Agent: quilt/0.69 Date: Tue, 11 Aug 2026 10:15:40 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Joe Lawrence , Andrey Grodzovsky Subject: [for-next][PATCH 2/2] selftests/livepatch: update test-ftrace.sh for deprecated ftrace_enabled References: <20260811141538.174498661@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 From: Andrey Grodzovsky kernel.ftrace_enabled=0 is now refused on kernels that deprecate the knob, so the old disable/reload flow no longer applies there. Probe for this with ftrace_disable_supported() and keep the full original scenario (disable, fail to load a livepatch, re-enable, load, confirm disable is refused while loaded) on kernels where it still works; otherwise just confirm the write is refused. Link: https://patch.msgid.link/20260806153000.4184871-3-andrey.grodzovsky@crowdstrike.com Suggested-by: Steven Rostedt Suggested-by: Joe Lawrence Assisted-by: Claude:claude-sonnet-5 Signed-off-by: Andrey Grodzovsky Signed-off-by: Steven Rostedt --- .../testing/selftests/livepatch/functions.sh | 14 ++++++ .../selftests/livepatch/test-ftrace.sh | 45 ++++++++++++------- 2 files changed, 42 insertions(+), 17 deletions(-) diff --git a/tools/testing/selftests/livepatch/functions.sh b/tools/testing/selftests/livepatch/functions.sh index 30dc677b2f45..a65b7b1ac8ad 100644 --- a/tools/testing/selftests/livepatch/functions.sh +++ b/tools/testing/selftests/livepatch/functions.sh @@ -126,6 +126,20 @@ function set_ftrace_enabled() { echo "livepatch: kernel.ftrace_enabled = $result" > /dev/kmsg } +# ftrace_disable_supported() - probe whether kernel.ftrace_enabled=0 +# can still disable ftrace on this kernel. Newer kernels deprecate +# the knob and always refuse the write with -EOPNOTSUPP. +function ftrace_disable_supported() { + local orig result + + orig=$(sysctl --values kernel.ftrace_enabled) + sysctl -q kernel.ftrace_enabled=0 &> /dev/null + result=$(sysctl --values kernel.ftrace_enabled) + sysctl -q "kernel.ftrace_enabled=$orig" &> /dev/null + + [[ "$result" == "0" ]] +} + function cleanup() { pop_config } diff --git a/tools/testing/selftests/livepatch/test-ftrace.sh b/tools/testing/selftests/livepatch/test-ftrace.sh index d2c3dea63104..cd27148510f8 100755 --- a/tools/testing/selftests/livepatch/test-ftrace.sh +++ b/tools/testing/selftests/livepatch/test-ftrace.sh @@ -12,29 +12,32 @@ setup_config # - turn ftrace_enabled OFF and verify livepatches can't load # - turn ftrace_enabled ON and verify livepatch can load # - verify that ftrace_enabled can't be turned OFF while a livepatch is loaded +# (skipped on kernels where the sysctl is deprecated and always refuses 0) start_test "livepatch interaction with ftrace_enabled sysctl" -set_ftrace_enabled 0 -load_failing_mod $MOD_LIVEPATCH +if ftrace_disable_supported; then -set_ftrace_enabled 1 -load_lp $MOD_LIVEPATCH -if [[ "$(cat /proc/cmdline)" != "$MOD_LIVEPATCH: this has been live patched" ]] ; then - echo -e "FAIL\n\n" - die "livepatch kselftest(s) failed" -fi + set_ftrace_enabled 0 + load_failing_mod $MOD_LIVEPATCH -# Check that ftrace could not get disabled when a livepatch is enabled -set_ftrace_enabled --fail 0 -if [[ "$(cat /proc/cmdline)" != "$MOD_LIVEPATCH: this has been live patched" ]] ; then - echo -e "FAIL\n\n" - die "livepatch kselftest(s) failed" -fi -disable_lp $MOD_LIVEPATCH -unload_lp $MOD_LIVEPATCH + set_ftrace_enabled 1 + load_lp $MOD_LIVEPATCH + if [[ "$(cat /proc/cmdline)" != "$MOD_LIVEPATCH: this has been live patched" ]] ; then + echo -e "FAIL\n\n" + die "livepatch kselftest(s) failed" + fi -check_result "livepatch: kernel.ftrace_enabled = 0 + # Check that ftrace could not get disabled when a livepatch is enabled + set_ftrace_enabled --fail 0 + if [[ "$(cat /proc/cmdline)" != "$MOD_LIVEPATCH: this has been live patched" ]] ; then + echo -e "FAIL\n\n" + die "livepatch kselftest(s) failed" + fi + disable_lp $MOD_LIVEPATCH + unload_lp $MOD_LIVEPATCH + + check_result "livepatch: kernel.ftrace_enabled = 0 % insmod test_modules/$MOD_LIVEPATCH.ko livepatch: enabling patch '$MOD_LIVEPATCH' livepatch: '$MOD_LIVEPATCH': initializing patching transition @@ -60,6 +63,14 @@ livepatch: '$MOD_LIVEPATCH': completing unpatching transition livepatch: '$MOD_LIVEPATCH': unpatching complete % rmmod $MOD_LIVEPATCH" +else + + set_ftrace_enabled --fail 0 + check_result "livepatch: sysctl: setting key \"kernel.ftrace_enabled\": \ +Operation not supported" + +fi + # - verify livepatch can load # - check if traces have a patched function -- 2.53.0