From: Joe Lawrence joe.lawrence@redhat.com
Since livepatching depends upon ftrace handlers to implement "patched" code functionality, verify that the ftrace_enabled sysctl value interacts with livepatch registration as expected. At the same time, ensure that ftrace_enabled is set and part of the test environment configuration that is saved and restored when running the selftests.
Signed-off-by: Joe Lawrence joe.lawrence@redhat.com Signed-off-by: Miroslav Benes mbenes@suse.cz --- tools/testing/selftests/livepatch/Makefile | 3 +- .../testing/selftests/livepatch/functions.sh | 14 +++- .../selftests/livepatch/test-ftrace.sh | 65 +++++++++++++++++++ 3 files changed, 80 insertions(+), 2 deletions(-) create mode 100755 tools/testing/selftests/livepatch/test-ftrace.sh
diff --git a/tools/testing/selftests/livepatch/Makefile b/tools/testing/selftests/livepatch/Makefile index fd405402c3ff..1886d9d94b88 100644 --- a/tools/testing/selftests/livepatch/Makefile +++ b/tools/testing/selftests/livepatch/Makefile @@ -4,6 +4,7 @@ TEST_PROGS_EXTENDED := functions.sh TEST_PROGS := \ test-livepatch.sh \ test-callbacks.sh \ - test-shadow-vars.sh + test-shadow-vars.sh \ + test-ftrace.sh
include ../lib.mk diff --git a/tools/testing/selftests/livepatch/functions.sh b/tools/testing/selftests/livepatch/functions.sh index b7e5a67ae434..31eb09e38729 100644 --- a/tools/testing/selftests/livepatch/functions.sh +++ b/tools/testing/selftests/livepatch/functions.sh @@ -32,12 +32,16 @@ function die() { function push_config() { DYNAMIC_DEBUG=$(grep '^kernel/livepatch' /sys/kernel/debug/dynamic_debug/control | \ awk -F'[: ]' '{print "file " $1 " line " $2 " " $4}') + FTRACE_ENABLED=$(sysctl --values kernel.ftrace_enabled) }
function pop_config() { if [[ -n "$DYNAMIC_DEBUG" ]]; then echo -n "$DYNAMIC_DEBUG" > /sys/kernel/debug/dynamic_debug/control fi + if [[ -n "$FTRACE_ENABLED" ]]; then + sysctl kernel.ftrace_enabled="$FTRACE_ENABLED" &> /dev/null + fi }
function set_dynamic_debug() { @@ -47,12 +51,20 @@ function set_dynamic_debug() { EOF }
+function set_ftrace_enabled() { + local sysctl="$1" + result=$(sysctl kernel.ftrace_enabled="$1" 2>&1 | paste --serial --delimiters=' ') + echo "livepatch: $result" > /dev/kmsg +} + # setup_config - save the current config and set a script exit trap that # restores the original config. Setup the dynamic debug -# for verbose livepatching output. +# for verbose livepatching output and turn on +# the ftrace_enabled sysctl. function setup_config() { push_config set_dynamic_debug + set_ftrace_enabled 1 trap pop_config EXIT INT TERM HUP }
diff --git a/tools/testing/selftests/livepatch/test-ftrace.sh b/tools/testing/selftests/livepatch/test-ftrace.sh new file mode 100755 index 000000000000..e2a76887f40a --- /dev/null +++ b/tools/testing/selftests/livepatch/test-ftrace.sh @@ -0,0 +1,65 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# Copyright (C) 2019 Joe Lawrence joe.lawrence@redhat.com + +. $(dirname $0)/functions.sh + +MOD_LIVEPATCH=test_klp_livepatch + +setup_config + + +# TEST: livepatch interaction with ftrace_enabled sysctl +# - 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 + +echo -n "TEST: livepatch interaction with ftrace_enabled sysctl ... " +dmesg -C + +set_ftrace_enabled 0 +load_failing_mod $MOD_LIVEPATCH + +set_ftrace_enabled 1 +load_lp $MOD_LIVEPATCH +if [[ "$(cat /proc/cmdline)" != "$MOD_LIVEPATCH: this has been live patched" ]] ; then + echo -e "FAIL\n\n" + die "livepatch kselftest(s) failed" +fi + +set_ftrace_enabled 0 +if [[ "$(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 +% modprobe $MOD_LIVEPATCH +livepatch: enabling patch '$MOD_LIVEPATCH' +livepatch: '$MOD_LIVEPATCH': initializing patching transition +livepatch: failed to register ftrace handler for function 'cmdline_proc_show' (-16) +livepatch: failed to patch object 'vmlinux' +livepatch: failed to enable patch '$MOD_LIVEPATCH' +livepatch: '$MOD_LIVEPATCH': canceling patching transition, going to unpatch +livepatch: '$MOD_LIVEPATCH': completing unpatching transition +livepatch: '$MOD_LIVEPATCH': unpatching complete +modprobe: ERROR: could not insert '$MOD_LIVEPATCH': Device or resource busy +livepatch: kernel.ftrace_enabled = 1 +% modprobe $MOD_LIVEPATCH +livepatch: enabling patch '$MOD_LIVEPATCH' +livepatch: '$MOD_LIVEPATCH': initializing patching transition +livepatch: '$MOD_LIVEPATCH': starting patching transition +livepatch: '$MOD_LIVEPATCH': completing patching transition +livepatch: '$MOD_LIVEPATCH': patching complete +livepatch: sysctl: setting key "kernel.ftrace_enabled": Device or resource busy kernel.ftrace_enabled = 0 +% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled +livepatch: '$MOD_LIVEPATCH': initializing unpatching transition +livepatch: '$MOD_LIVEPATCH': starting unpatching transition +livepatch: '$MOD_LIVEPATCH': completing unpatching transition +livepatch: '$MOD_LIVEPATCH': unpatching complete +% rmmod $MOD_LIVEPATCH" + + +exit 0