[PATCH v8 9/9] selftests/livepatch: Add function test for provides/obsoletes
From: Yafang Shao <hidden>
Date: 2026-09-09 02:44:21
Subsystem:
kernel selftest framework, live patching, the rest · Maintainers:
Shuah Khan, Shuah Khan, Josh Poimboeuf, Jiri Kosina, Miroslav Benes, Petr Mladek, Linus Torvalds
Livepatches with different provides ids must not modify the same function, unless they share the same provides id or the second livepatch obsoletes the first one. Add test scenarios that verify this rule on the combination of patched functions and provides ids. These tests are skipped on kernels that still support the legacy "replace" attribute. Suggested-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Yafang Shao <redacted> --- .../livepatch/test-provides-obsoletes.sh | 176 ++++++++++++++++++ .../selftests/livepatch/test_modules/Makefile | 1 + .../test_modules/test_klp_meminfo_lp2.c | 1 + 3 files changed, 178 insertions(+) create mode 100644 tools/testing/selftests/livepatch/test_modules/test_klp_meminfo_lp2.c
diff --git a/tools/testing/selftests/livepatch/test-provides-obsoletes.sh b/tools/testing/selftests/livepatch/test-provides-obsoletes.sh
index 8b7b5eded80c..d4443cb81e90 100755
--- a/tools/testing/selftests/livepatch/test-provides-obsoletes.sh
+++ b/tools/testing/selftests/livepatch/test-provides-obsoletes.sh@@ -5,6 +5,7 @@ . $(dirname $0)/functions.sh MOD_MEMINFO=test_klp_meminfo_lp +MOD_MEMINFO2=test_klp_meminfo_lp2 MOD_CMDLINE=test_klp_cmdline_lp MOD_STATE=test_klp_state MOD_STATE2=test_klp_state2
@@ -449,4 +450,179 @@ $MOD_STATE2: free_loglevel_state: freeing space for the stored console_loglevel livepatch: '$MOD_STATE2': unpatching complete % rmmod $MOD_STATE2" + +# - load two livepatches that modify the same function +# (meminfo_proc_show), both with provides=1. The second livepatch +# replaces the first one because of the same provides id, even +# though they share the patched function. +# - verify that the first livepatch is gone from sysfs (replaced) +# and that the second one is enabled +# - unload the replacing livepatch, then the replaced one + +start_test "same function, replaced by provides" + +load_lp $MOD_MEMINFO provides=1 +load_lp $MOD_MEMINFO2 provides=1 + +loop_until '[[ ! -e "$SYSFS_KLP_DIR/$MOD_MEMINFO" ]]' || + die "failed to replace $MOD_MEMINFO" +check_sysfs_value "$MOD_MEMINFO2" "provides" "1" + +disable_lp $MOD_MEMINFO2 +unload_lp $MOD_MEMINFO2 +unload_lp $MOD_MEMINFO + +check_result "% insmod test_modules/$MOD_MEMINFO.ko provides=1 +livepatch: enabling patch '$MOD_MEMINFO' +livepatch: '$MOD_MEMINFO': initializing patching transition +livepatch: '$MOD_MEMINFO': starting patching transition +livepatch: '$MOD_MEMINFO': completing patching transition +livepatch: '$MOD_MEMINFO': patching complete +% insmod test_modules/$MOD_MEMINFO2.ko provides=1 +livepatch: enabling patch '$MOD_MEMINFO2' +livepatch: '$MOD_MEMINFO2': initializing patching transition +livepatch: '$MOD_MEMINFO2': starting patching transition +livepatch: '$MOD_MEMINFO2': completing patching transition +livepatch: '$MOD_MEMINFO2': patching complete +% echo 0 > $SYSFS_KLP_DIR/$MOD_MEMINFO2/enabled +livepatch: '$MOD_MEMINFO2': initializing unpatching transition +livepatch: '$MOD_MEMINFO2': starting unpatching transition +livepatch: '$MOD_MEMINFO2': completing unpatching transition +livepatch: '$MOD_MEMINFO2': unpatching complete +% rmmod $MOD_MEMINFO2 +% rmmod $MOD_MEMINFO" + + +# - load a livepatch that modifies meminfo_proc_show with provides=1, +# then try to load another livepatch that modifies the same +# function with a different provides id (provides=2). +# - since the provides ids differ, the second livepatch would not +# replace the first one; the same function can not be handled by +# two different provides groups in parallel, so the load must fail. +# - unload the first livepatch + +start_test "same function, can't be loaded in parallel" + +load_lp $MOD_MEMINFO provides=1 +load_failing_mod $MOD_MEMINFO2 provides=2 + +disable_lp $MOD_MEMINFO +unload_lp $MOD_MEMINFO + +check_result "% insmod test_modules/$MOD_MEMINFO.ko provides=1 +livepatch: enabling patch '$MOD_MEMINFO' +livepatch: '$MOD_MEMINFO': initializing patching transition +livepatch: '$MOD_MEMINFO': starting patching transition +livepatch: '$MOD_MEMINFO': completing patching transition +livepatch: '$MOD_MEMINFO': patching complete +% insmod test_modules/$MOD_MEMINFO2.ko provides=2 +livepatch: Livepatch patch ($MOD_MEMINFO2) is not compatible with the already installed livepatches. +insmod: ERROR: could not insert module test_modules/$MOD_MEMINFO2.ko: Invalid parameters +% echo 0 > $SYSFS_KLP_DIR/$MOD_MEMINFO/enabled +livepatch: '$MOD_MEMINFO': initializing unpatching transition +livepatch: '$MOD_MEMINFO': starting unpatching transition +livepatch: '$MOD_MEMINFO': completing unpatching transition +livepatch: '$MOD_MEMINFO': unpatching complete +% rmmod $MOD_MEMINFO" + + +# - load a livepatch that modifies meminfo_proc_show with provides=1, +# then another livepatch with provides=1 that modifies a different +# function (cmdline_proc_show). The second one replaces the first +# one because of the same provides id. +# - since the patched functions differ, the replacement does not need +# to restore the old function body; the transition only switches +# the ftrace nops, i.e. the atomic replace (nops) path. +# - after the replacement /proc/meminfo is no longer patched, while +# /proc/cmdline is patched +# - unload the replacing livepatch, then the replaced one + +start_test "different functions, atomic replace works (nops)" + +load_lp $MOD_MEMINFO provides=1 + +grep 'live patched' /proc/meminfo > /dev/kmsg + +load_lp $MOD_CMDLINE provides=1 + +grep 'live patched' /proc/cmdline > /dev/kmsg + +disable_lp $MOD_CMDLINE +unload_lp $MOD_CMDLINE +unload_lp $MOD_MEMINFO + +check_result "% insmod test_modules/$MOD_MEMINFO.ko provides=1 +livepatch: enabling patch '$MOD_MEMINFO' +livepatch: '$MOD_MEMINFO': initializing patching transition +livepatch: '$MOD_MEMINFO': starting patching transition +livepatch: '$MOD_MEMINFO': completing patching transition +livepatch: '$MOD_MEMINFO': patching complete +$MOD_MEMINFO: this has been live patched +% insmod test_modules/$MOD_CMDLINE.ko provides=1 +livepatch: enabling patch '$MOD_CMDLINE' +livepatch: '$MOD_CMDLINE': initializing patching transition +livepatch: '$MOD_CMDLINE': starting patching transition +livepatch: '$MOD_CMDLINE': completing patching transition +livepatch: '$MOD_CMDLINE': patching complete +$MOD_CMDLINE: this has been live patched +% echo 0 > $SYSFS_KLP_DIR/$MOD_CMDLINE/enabled +livepatch: '$MOD_CMDLINE': initializing unpatching transition +livepatch: '$MOD_CMDLINE': starting unpatching transition +livepatch: '$MOD_CMDLINE': completing unpatching transition +livepatch: '$MOD_CMDLINE': unpatching complete +% rmmod $MOD_CMDLINE +% rmmod $MOD_MEMINFO" + + +# - load two livepatches with different provides ids (1 and 2) that +# modify different functions (meminfo_proc_show and +# cmdline_proc_show). Neither of them replaces the other, so both +# livepatches must coexist. +# - verify that both /proc/meminfo and /proc/cmdline are patched +# - disable and unload both livepatches + +start_test "different functions, install in parallel" + +load_lp $MOD_MEMINFO provides=1 + +grep 'live patched' /proc/meminfo > /dev/kmsg + +load_lp $MOD_CMDLINE provides=2 + +grep 'live patched' /proc/meminfo > /dev/kmsg +grep 'live patched' /proc/cmdline > /dev/kmsg + +disable_lp $MOD_MEMINFO +unload_lp $MOD_MEMINFO +disable_lp $MOD_CMDLINE +unload_lp $MOD_CMDLINE + +check_result "% insmod test_modules/$MOD_MEMINFO.ko provides=1 +livepatch: enabling patch '$MOD_MEMINFO' +livepatch: '$MOD_MEMINFO': initializing patching transition +livepatch: '$MOD_MEMINFO': starting patching transition +livepatch: '$MOD_MEMINFO': completing patching transition +livepatch: '$MOD_MEMINFO': patching complete +$MOD_MEMINFO: this has been live patched +% insmod test_modules/$MOD_CMDLINE.ko provides=2 +livepatch: enabling patch '$MOD_CMDLINE' +livepatch: '$MOD_CMDLINE': initializing patching transition +livepatch: '$MOD_CMDLINE': starting patching transition +livepatch: '$MOD_CMDLINE': completing patching transition +livepatch: '$MOD_CMDLINE': patching complete +$MOD_MEMINFO: this has been live patched +$MOD_CMDLINE: this has been live patched +% echo 0 > $SYSFS_KLP_DIR/$MOD_MEMINFO/enabled +livepatch: '$MOD_MEMINFO': initializing unpatching transition +livepatch: '$MOD_MEMINFO': starting unpatching transition +livepatch: '$MOD_MEMINFO': completing unpatching transition +livepatch: '$MOD_MEMINFO': unpatching complete +% rmmod $MOD_MEMINFO +% echo 0 > $SYSFS_KLP_DIR/$MOD_CMDLINE/enabled +livepatch: '$MOD_CMDLINE': initializing unpatching transition +livepatch: '$MOD_CMDLINE': starting unpatching transition +livepatch: '$MOD_CMDLINE': completing unpatching transition +livepatch: '$MOD_CMDLINE': unpatching complete +% rmmod $MOD_CMDLINE" + exit 0
diff --git a/tools/testing/selftests/livepatch/test_modules/Makefile b/tools/testing/selftests/livepatch/test_modules/Makefile
index 732e0003930b..0c17754997d2 100644
--- a/tools/testing/selftests/livepatch/test_modules/Makefile
+++ b/tools/testing/selftests/livepatch/test_modules/Makefile@@ -2,6 +2,7 @@ TESTMODS_DIR := $(realpath $(dir $(abspath $(lastword $(MAKEFILE_LIST))))) KDIR ?= /lib/modules/$(shell uname -r)/build obj-m += test_klp_meminfo_lp.o \ + test_klp_meminfo_lp2.o \ test_klp_callbacks_busy.o \ test_klp_callbacks_demo.o \ test_klp_callbacks_demo2.o \
diff --git a/tools/testing/selftests/livepatch/test_modules/test_klp_meminfo_lp2.c b/tools/testing/selftests/livepatch/test_modules/test_klp_meminfo_lp2.c
new file mode 100644
index 000000000000..c82827207f10
--- /dev/null
+++ b/tools/testing/selftests/livepatch/test_modules/test_klp_meminfo_lp2.c@@ -0,0 +1 @@ +#include "test_klp_meminfo_lp.c"
--
2.52.0