Merge: livepatch: selected fixes for rhel-10.1

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-10/-/merge_requests/457

JIRA: https://issues.redhat.com/browse/RHEL-80216



A small series of livepatch fixes for rhel-10.1

Signed-off-by: Ryan Sullivan <rysulliv@redhat.com>

Approved-by: Joe Lawrence <joe.lawrence@redhat.com>
Approved-by: Rado Vrbovsky <rvrbovsk@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Julio Faracco <jfaracco@redhat.com>

tools/testing/selftests/livepatch/Makefile

@@ -10,7 +10,8 @@ TEST_PROGS := \
 	test-state.sh \
 	test-ftrace.sh \
 	test-sysfs.sh \
-	test-syscall.sh
+	test-syscall.sh \
+	test-kprobe.sh
 
 TEST_FILES := settings
 

tools/testing/selftests/livepatch/functions.sh

@@ -6,7 +6,10 @@
 
 MAX_RETRIES=600
 RETRY_INTERVAL=".1"	# seconds
-KLP_SYSFS_DIR="/sys/kernel/livepatch"
+SYSFS_KERNEL_DIR="/sys/kernel"
+SYSFS_KLP_DIR="$SYSFS_KERNEL_DIR/livepatch"
+SYSFS_DEBUG_DIR="$SYSFS_KERNEL_DIR/debug"
+SYSFS_KPROBES_DIR="$SYSFS_DEBUG_DIR/kprobes"
 
 # Kselftest framework requirement - SKIP code is 4
 ksft_skip=4
@@ -55,22 +58,26 @@ function die() {
 }
 
 function push_config() {
-	DYNAMIC_DEBUG=$(grep '^kernel/livepatch' /sys/kernel/debug/dynamic_debug/control | \
+	DYNAMIC_DEBUG=$(grep '^kernel/livepatch' "$SYSFS_DEBUG_DIR/dynamic_debug/control" | \
 			awk -F'[: ]' '{print "file " $1 " line " $2 " " $4}')
 	FTRACE_ENABLED=$(sysctl --values kernel.ftrace_enabled)
+	KPROBE_ENABLED=$(cat "$SYSFS_KPROBES_DIR/enabled")
 }
 
 function pop_config() {
 	if [[ -n "$DYNAMIC_DEBUG" ]]; then
-		echo -n "$DYNAMIC_DEBUG" > /sys/kernel/debug/dynamic_debug/control
+		echo -n "$DYNAMIC_DEBUG" > "$SYSFS_DEBUG_DIR/dynamic_debug/control"
 	fi
 	if [[ -n "$FTRACE_ENABLED" ]]; then
 		sysctl kernel.ftrace_enabled="$FTRACE_ENABLED" &> /dev/null
 	fi
+	if [[ -n "$KPROBE_ENABLED" ]]; then
+		echo "$KPROBE_ENABLED" > "$SYSFS_KPROBES_DIR/enabled"
+	fi
 }
 
 function set_dynamic_debug() {
-        cat <<-EOF > /sys/kernel/debug/dynamic_debug/control
+        cat <<-EOF > "$SYSFS_DEBUG_DIR/dynamic_debug/control"
 		file kernel/livepatch/* +p
 		func klp_try_switch_task -p
 		EOF
@@ -183,7 +190,7 @@ function load_lp_nowait() {
 	__load_mod "$mod" "$@"
 
 	# Wait for livepatch in sysfs ...
-	loop_until '[[ -e "/sys/kernel/livepatch/$mod" ]]' ||
+	loop_until '[[ -e "$SYSFS_KLP_DIR/$mod" ]]' ||
 		die "failed to load module $mod (sysfs)"
 }
 
@@ -196,7 +203,7 @@ function load_lp() {
 	load_lp_nowait "$mod" "$@"
 
 	# Wait until the transition finishes ...
-	loop_until 'grep -q '^0$' /sys/kernel/livepatch/$mod/transition' ||
+	loop_until 'grep -q '^0$' $SYSFS_KLP_DIR/$mod/transition' ||
 		die "failed to complete transition"
 }
 
@@ -246,12 +253,12 @@ function unload_lp() {
 function disable_lp() {
 	local mod="$1"
 
-	log "% echo 0 > /sys/kernel/livepatch/$mod/enabled"
-	echo 0 > /sys/kernel/livepatch/"$mod"/enabled
+	log "% echo 0 > $SYSFS_KLP_DIR/$mod/enabled"
+	echo 0 > "$SYSFS_KLP_DIR/$mod/enabled"
 
 	# Wait until the transition finishes and the livepatch gets
 	# removed from sysfs...
-	loop_until '[[ ! -e "/sys/kernel/livepatch/$mod" ]]' ||
+	loop_until '[[ ! -e "$SYSFS_KLP_DIR/$mod" ]]' ||
 		die "failed to disable livepatch $mod"
 }
 
@@ -322,7 +329,7 @@ function check_sysfs_rights() {
 	local rel_path="$1"; shift
 	local expected_rights="$1"; shift
 
-	local path="$KLP_SYSFS_DIR/$mod/$rel_path"
+	local path="$SYSFS_KLP_DIR/$mod/$rel_path"
 	local rights=$(/bin/stat --format '%A' "$path")
 	if test "$rights" != "$expected_rights" ; then
 		die "Unexpected access rights of $path: $expected_rights vs. $rights"
@@ -338,7 +345,7 @@ function check_sysfs_value() {
 	local rel_path="$1"; shift
 	local expected_value="$1"; shift
 
-	local path="$KLP_SYSFS_DIR/$mod/$rel_path"
+	local path="$SYSFS_KLP_DIR/$mod/$rel_path"
 	local value=`cat $path`
 	if test "$value" != "$expected_value" ; then
 		die "Unexpected value in $path: $expected_value vs. $value"

tools/testing/selftests/livepatch/test-callbacks.sh

@@ -46,7 +46,7 @@ livepatch: '$MOD_LIVEPATCH': completing patching transition
 $MOD_LIVEPATCH: post_patch_callback: vmlinux
 $MOD_LIVEPATCH: post_patch_callback: $MOD_TARGET -> [MODULE_STATE_LIVE] Normal state
 livepatch: '$MOD_LIVEPATCH': patching complete
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
 livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
 $MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
 $MOD_LIVEPATCH: pre_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_LIVE] Normal state
@@ -94,7 +94,7 @@ livepatch: applying patch '$MOD_LIVEPATCH' to loading module '$MOD_TARGET'
 $MOD_LIVEPATCH: pre_patch_callback: $MOD_TARGET -> [MODULE_STATE_COMING] Full formed, running module_init
 $MOD_LIVEPATCH: post_patch_callback: $MOD_TARGET -> [MODULE_STATE_COMING] Full formed, running module_init
 $MOD_TARGET: ${MOD_TARGET}_init
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
 livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
 $MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
 $MOD_LIVEPATCH: pre_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_LIVE] Normal state
@@ -146,7 +146,7 @@ $MOD_TARGET: ${MOD_TARGET}_exit
 $MOD_LIVEPATCH: pre_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_GOING] Going away
 livepatch: reverting patch '$MOD_LIVEPATCH' on unloading module '$MOD_TARGET'
 $MOD_LIVEPATCH: post_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_GOING] Going away
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
 livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
 $MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
 livepatch: '$MOD_LIVEPATCH': starting unpatching transition
@@ -195,7 +195,7 @@ $MOD_TARGET: ${MOD_TARGET}_exit
 $MOD_LIVEPATCH: pre_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_GOING] Going away
 livepatch: reverting patch '$MOD_LIVEPATCH' on unloading module '$MOD_TARGET'
 $MOD_LIVEPATCH: post_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_GOING] Going away
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
 livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
 $MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
 livepatch: '$MOD_LIVEPATCH': starting unpatching transition
@@ -227,7 +227,7 @@ livepatch: '$MOD_LIVEPATCH': starting patching transition
 livepatch: '$MOD_LIVEPATCH': completing patching transition
 $MOD_LIVEPATCH: post_patch_callback: vmlinux
 livepatch: '$MOD_LIVEPATCH': patching complete
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
 livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
 $MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
 livepatch: '$MOD_LIVEPATCH': starting unpatching transition
@@ -310,7 +310,7 @@ $MOD_LIVEPATCH: pre_patch_callback: $MOD_TARGET -> [MODULE_STATE_COMING] Full fo
 livepatch: pre-patch callback failed for object '$MOD_TARGET'
 livepatch: patch '$MOD_LIVEPATCH' failed for module '$MOD_TARGET', refusing to load module '$MOD_TARGET'
 insmod: ERROR: could not insert module test_modules/$MOD_TARGET.ko: No such device
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
 livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
 $MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
 livepatch: '$MOD_LIVEPATCH': starting unpatching transition
@@ -364,7 +364,7 @@ $MOD_TARGET: ${MOD_TARGET}_exit
 $MOD_LIVEPATCH: pre_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_GOING] Going away
 livepatch: reverting patch '$MOD_LIVEPATCH' on unloading module '$MOD_TARGET'
 $MOD_LIVEPATCH: post_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_GOING] Going away
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
 livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
 $MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
 $MOD_LIVEPATCH: pre_unpatch_callback: $MOD_TARGET_BUSY -> [MODULE_STATE_LIVE] Normal state
@@ -412,7 +412,7 @@ load_lp_nowait $MOD_LIVEPATCH
 
 # Wait until the livepatch reports in-transition state, i.e. that it's
 # stalled on $MOD_TARGET_BUSY::busymod_work_func()
-loop_until 'grep -q '^1$' /sys/kernel/livepatch/$MOD_LIVEPATCH/transition' ||
+loop_until 'grep -q '^1$' $SYSFS_KLP_DIR/$MOD_LIVEPATCH/transition' ||
 	die "failed to stall transition"
 
 load_mod $MOD_TARGET
@@ -438,7 +438,7 @@ $MOD_TARGET: ${MOD_TARGET}_init
 $MOD_TARGET: ${MOD_TARGET}_exit
 livepatch: reverting patch '$MOD_LIVEPATCH' on unloading module '$MOD_TARGET'
 $MOD_LIVEPATCH: post_unpatch_callback: $MOD_TARGET -> [MODULE_STATE_GOING] Going away
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
 livepatch: '$MOD_LIVEPATCH': reversing transition from patching to unpatching
 livepatch: '$MOD_LIVEPATCH': starting unpatching transition
 livepatch: '$MOD_LIVEPATCH': completing unpatching transition
@@ -483,14 +483,14 @@ livepatch: '$MOD_LIVEPATCH2': starting patching transition
 livepatch: '$MOD_LIVEPATCH2': completing patching transition
 $MOD_LIVEPATCH2: post_patch_callback: vmlinux
 livepatch: '$MOD_LIVEPATCH2': patching complete
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH2/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH2/enabled
 livepatch: '$MOD_LIVEPATCH2': initializing unpatching transition
 $MOD_LIVEPATCH2: pre_unpatch_callback: vmlinux
 livepatch: '$MOD_LIVEPATCH2': starting unpatching transition
 livepatch: '$MOD_LIVEPATCH2': completing unpatching transition
 $MOD_LIVEPATCH2: post_unpatch_callback: vmlinux
 livepatch: '$MOD_LIVEPATCH2': unpatching complete
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
 livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
 $MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
 livepatch: '$MOD_LIVEPATCH': starting unpatching transition
@@ -539,7 +539,7 @@ livepatch: '$MOD_LIVEPATCH2': starting patching transition
 livepatch: '$MOD_LIVEPATCH2': completing patching transition
 $MOD_LIVEPATCH2: post_patch_callback: vmlinux
 livepatch: '$MOD_LIVEPATCH2': patching complete
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH2/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH2/enabled
 livepatch: '$MOD_LIVEPATCH2': initializing unpatching transition
 $MOD_LIVEPATCH2: pre_unpatch_callback: vmlinux
 livepatch: '$MOD_LIVEPATCH2': starting unpatching transition

tools/testing/selftests/livepatch/test-ftrace.sh

@@ -53,7 +53,7 @@ livepatch: '$MOD_LIVEPATCH': starting patching transition
 livepatch: '$MOD_LIVEPATCH': completing patching transition
 livepatch: '$MOD_LIVEPATCH': patching complete
 livepatch: sysctl: setting key \"kernel.ftrace_enabled\": Device or resource busy
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
 livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
 livepatch: '$MOD_LIVEPATCH': starting unpatching transition
 livepatch: '$MOD_LIVEPATCH': completing unpatching transition

tools/testing/selftests/livepatch/test-kprobe.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2024 SUSE
+# Author: Michael Vetter <mvetter@suse.com>
+
+. $(dirname $0)/functions.sh
+
+MOD_LIVEPATCH=test_klp_livepatch
+MOD_KPROBE=test_klp_kprobe
+
+setup_config
+
+# Kprobe a function and verify that we can't livepatch that same function
+# when it uses a post_handler since only one IPMODIFY maybe be registered
+# to any given function at a time.
+
+start_test "livepatch interaction with kprobed function with post_handler"
+
+echo 1 > "$SYSFS_KPROBES_DIR/enabled"
+
+load_mod $MOD_KPROBE has_post_handler=true
+load_failing_mod $MOD_LIVEPATCH
+unload_mod $MOD_KPROBE
+
+check_result "% insmod test_modules/test_klp_kprobe.ko has_post_handler=true
+% insmod test_modules/$MOD_LIVEPATCH.ko
+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
+insmod: ERROR: could not insert module test_modules/$MOD_LIVEPATCH.ko: Device or resource busy
+% rmmod test_klp_kprobe"
+
+start_test "livepatch interaction with kprobed function without post_handler"
+
+load_mod $MOD_KPROBE has_post_handler=false
+load_lp $MOD_LIVEPATCH
+
+unload_mod $MOD_KPROBE
+disable_lp $MOD_LIVEPATCH
+unload_lp $MOD_LIVEPATCH
+
+check_result "% insmod test_modules/test_klp_kprobe.ko has_post_handler=false
+% insmod test_modules/$MOD_LIVEPATCH.ko
+livepatch: enabling patch '$MOD_LIVEPATCH'
+livepatch: '$MOD_LIVEPATCH': initializing patching transition
+livepatch: '$MOD_LIVEPATCH': starting patching transition
+livepatch: '$MOD_LIVEPATCH': completing patching transition
+livepatch: '$MOD_LIVEPATCH': patching complete
+% rmmod test_klp_kprobe
+% echo 0 > /sys/kernel/livepatch/$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

tools/testing/selftests/livepatch/test-livepatch.sh

@@ -39,7 +39,7 @@ livepatch: '$MOD_LIVEPATCH1': initializing patching transition
 livepatch: '$MOD_LIVEPATCH1': starting patching transition
 livepatch: '$MOD_LIVEPATCH1': completing patching transition
 livepatch: '$MOD_LIVEPATCH1': patching complete
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH1/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH1/enabled
 livepatch: '$MOD_LIVEPATCH1': initializing unpatching transition
 livepatch: '$MOD_LIVEPATCH1': starting unpatching transition
 livepatch: '$MOD_LIVEPATCH1': completing unpatching transition
@@ -92,14 +92,14 @@ livepatch: '$MOD_REPLACE': completing patching transition
 livepatch: '$MOD_REPLACE': patching complete
 $MOD_LIVEPATCH1: this has been live patched
 $MOD_REPLACE: this has been live patched
-% echo 0 > /sys/kernel/livepatch/$MOD_REPLACE/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_REPLACE/enabled
 livepatch: '$MOD_REPLACE': initializing unpatching transition
 livepatch: '$MOD_REPLACE': starting unpatching transition
 livepatch: '$MOD_REPLACE': completing unpatching transition
 livepatch: '$MOD_REPLACE': unpatching complete
 % rmmod $MOD_REPLACE
 $MOD_LIVEPATCH1: this has been live patched
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH1/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH1/enabled
 livepatch: '$MOD_LIVEPATCH1': initializing unpatching transition
 livepatch: '$MOD_LIVEPATCH1': starting unpatching transition
 livepatch: '$MOD_LIVEPATCH1': completing unpatching transition
@@ -128,7 +128,7 @@ for mod in $MOD_LIVEPATCH2 $MOD_LIVEPATCH3; do
 	load_lp "$mod"
 done
 
-mods=(/sys/kernel/livepatch/*)
+mods=($SYSFS_KLP_DIR/*)
 nmods=${#mods[@]}
 if [ "$nmods" -ne 3 ]; then
 	die "Expecting three modules listed, found $nmods"
@@ -139,7 +139,7 @@ load_lp $MOD_REPLACE replace=1
 grep 'live patched' /proc/cmdline > /dev/kmsg
 grep 'live patched' /proc/meminfo > /dev/kmsg
 
-loop_until 'mods=(/sys/kernel/livepatch/*); nmods=${#mods[@]}; [[ "$nmods" -eq 1 ]]' ||
+loop_until 'mods=($SYSFS_KLP_DIR/*); nmods=${#mods[@]}; [[ "$nmods" -eq 1 ]]' ||
         die "Expecting only one moduled listed, found $nmods"
 
 # These modules were disabled by the atomic replace
@@ -188,7 +188,7 @@ $MOD_REPLACE: this has been live patched
 % rmmod $MOD_LIVEPATCH2
 % rmmod $MOD_LIVEPATCH1
 $MOD_REPLACE: this has been live patched
-% echo 0 > /sys/kernel/livepatch/$MOD_REPLACE/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_REPLACE/enabled
 livepatch: '$MOD_REPLACE': initializing unpatching transition
 livepatch: '$MOD_REPLACE': starting unpatching transition
 livepatch: '$MOD_REPLACE': completing unpatching transition

tools/testing/selftests/livepatch/test-state.sh

@@ -29,7 +29,7 @@ livepatch: '$MOD_LIVEPATCH': completing patching transition
 $MOD_LIVEPATCH: post_patch_callback: vmlinux
 $MOD_LIVEPATCH: fix_console_loglevel: fixing console_loglevel
 livepatch: '$MOD_LIVEPATCH': patching complete
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
 livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
 $MOD_LIVEPATCH: pre_unpatch_callback: vmlinux
 $MOD_LIVEPATCH: restore_console_loglevel: restoring console_loglevel
@@ -72,7 +72,7 @@ $MOD_LIVEPATCH2: post_patch_callback: vmlinux
 $MOD_LIVEPATCH2: fix_console_loglevel: taking over the console_loglevel change
 livepatch: '$MOD_LIVEPATCH2': patching complete
 % rmmod $MOD_LIVEPATCH
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH2/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH2/enabled
 livepatch: '$MOD_LIVEPATCH2': initializing unpatching transition
 $MOD_LIVEPATCH2: pre_unpatch_callback: vmlinux
 $MOD_LIVEPATCH2: restore_console_loglevel: restoring console_loglevel
@@ -127,7 +127,7 @@ livepatch: '$MOD_LIVEPATCH2': completing patching transition
 $MOD_LIVEPATCH2: post_patch_callback: vmlinux
 $MOD_LIVEPATCH2: fix_console_loglevel: taking over the console_loglevel change
 livepatch: '$MOD_LIVEPATCH2': patching complete
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH2/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH2/enabled
 livepatch: '$MOD_LIVEPATCH2': initializing unpatching transition
 $MOD_LIVEPATCH2: pre_unpatch_callback: vmlinux
 $MOD_LIVEPATCH2: restore_console_loglevel: restoring console_loglevel
@@ -162,7 +162,7 @@ livepatch: '$MOD_LIVEPATCH2': patching complete
 % insmod test_modules/$MOD_LIVEPATCH.ko
 livepatch: Livepatch patch ($MOD_LIVEPATCH) is not compatible with the already installed livepatches.
 insmod: ERROR: could not insert module test_modules/$MOD_LIVEPATCH.ko: Invalid parameters
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH2/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH2/enabled
 livepatch: '$MOD_LIVEPATCH2': initializing unpatching transition
 $MOD_LIVEPATCH2: pre_unpatch_callback: vmlinux
 $MOD_LIVEPATCH2: restore_console_loglevel: restoring console_loglevel

tools/testing/selftests/livepatch/test-syscall.sh

@@ -27,9 +27,9 @@ pid_list=$(echo ${pids[@]} | tr ' ' ',')
 load_lp $MOD_SYSCALL klp_pids=$pid_list
 
 # wait for all tasks to transition to patched state
-loop_until 'grep -q '^0$' /sys/kernel/test_klp_syscall/npids'
+loop_until 'grep -q '^0$' $SYSFS_KERNEL_DIR/$MOD_SYSCALL/npids'
 
-pending_pids=$(cat /sys/kernel/test_klp_syscall/npids)
+pending_pids=$(cat $SYSFS_KERNEL_DIR/$MOD_SYSCALL/npids)
 log "$MOD_SYSCALL: Remaining not livepatched processes: $pending_pids"
 
 for pid in ${pids[@]}; do
@@ -46,7 +46,7 @@ livepatch: '$MOD_SYSCALL': starting patching transition
 livepatch: '$MOD_SYSCALL': completing patching transition
 livepatch: '$MOD_SYSCALL': patching complete
 $MOD_SYSCALL: Remaining not livepatched processes: 0
-% echo 0 > /sys/kernel/livepatch/$MOD_SYSCALL/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_SYSCALL/enabled
 livepatch: '$MOD_SYSCALL': initializing unpatching transition
 livepatch: '$MOD_SYSCALL': starting unpatching transition
 livepatch: '$MOD_SYSCALL': completing unpatching transition

tools/testing/selftests/livepatch/test-sysfs.sh

@@ -34,7 +34,7 @@ livepatch: '$MOD_LIVEPATCH': initializing patching transition
 livepatch: '$MOD_LIVEPATCH': starting patching transition
 livepatch: '$MOD_LIVEPATCH': completing patching transition
 livepatch: '$MOD_LIVEPATCH': patching complete
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
 livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
 livepatch: '$MOD_LIVEPATCH': starting unpatching transition
 livepatch: '$MOD_LIVEPATCH': completing unpatching transition
@@ -75,7 +75,7 @@ test_klp_callbacks_mod: test_klp_callbacks_mod_exit
 test_klp_callbacks_demo: pre_unpatch_callback: test_klp_callbacks_mod -> [MODULE_STATE_GOING] Going away
 livepatch: reverting patch 'test_klp_callbacks_demo' on unloading module 'test_klp_callbacks_mod'
 test_klp_callbacks_demo: post_unpatch_callback: test_klp_callbacks_mod -> [MODULE_STATE_GOING] Going away
-% echo 0 > /sys/kernel/livepatch/test_klp_callbacks_demo/enabled
+% echo 0 > $SYSFS_KLP_DIR/test_klp_callbacks_demo/enabled
 livepatch: 'test_klp_callbacks_demo': initializing unpatching transition
 test_klp_callbacks_demo: pre_unpatch_callback: vmlinux
 livepatch: 'test_klp_callbacks_demo': starting unpatching transition
@@ -101,7 +101,7 @@ livepatch: '$MOD_LIVEPATCH': initializing patching transition
 livepatch: '$MOD_LIVEPATCH': starting patching transition
 livepatch: '$MOD_LIVEPATCH': completing patching transition
 livepatch: '$MOD_LIVEPATCH': patching complete
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
 livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
 livepatch: '$MOD_LIVEPATCH': starting unpatching transition
 livepatch: '$MOD_LIVEPATCH': completing unpatching transition
@@ -124,7 +124,7 @@ livepatch: '$MOD_LIVEPATCH': initializing patching transition
 livepatch: '$MOD_LIVEPATCH': starting patching transition
 livepatch: '$MOD_LIVEPATCH': completing patching transition
 livepatch: '$MOD_LIVEPATCH': patching complete
-% echo 0 > /sys/kernel/livepatch/$MOD_LIVEPATCH/enabled
+% echo 0 > $SYSFS_KLP_DIR/$MOD_LIVEPATCH/enabled
 livepatch: '$MOD_LIVEPATCH': initializing unpatching transition
 livepatch: '$MOD_LIVEPATCH': starting unpatching transition
 livepatch: '$MOD_LIVEPATCH': completing unpatching transition

tools/testing/selftests/livepatch/test_modules/Makefile

@@ -6,11 +6,12 @@ obj-m += test_klp_atomic_replace.o \
 	test_klp_callbacks_demo.o \
 	test_klp_callbacks_demo2.o \
 	test_klp_callbacks_mod.o \
+	test_klp_kprobe.o \
 	test_klp_livepatch.o \
+	test_klp_shadow_vars.o \
 	test_klp_state.o \
 	test_klp_state2.o \
 	test_klp_state3.o \
-	test_klp_shadow_vars.o \
 	test_klp_syscall.o
 
 # Ensure that KDIR exists, otherwise skip the compilation

tools/testing/selftests/livepatch/test_modules/test_klp_kprobe.c

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2024 Marcos Paulo de Souza <mpdesouza@suse.com>
+// Copyright (C) 2024 Michael Vetter <mvetter@suse.com>
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/kprobes.h>
+
+static bool has_post_handler = true;
+module_param(has_post_handler, bool, 0444);
+
+static void __kprobes post_handler(struct kprobe *p, struct pt_regs *regs,
+				unsigned long flags)
+{
+}
+
+static struct kprobe kp = {
+	.symbol_name = "cmdline_proc_show",
+};
+
+static int __init kprobe_init(void)
+{
+	if (has_post_handler)
+		kp.post_handler = post_handler;
+
+	return register_kprobe(&kp);
+}
+
+static void __exit kprobe_exit(void)
+{
+	unregister_kprobe(&kp);
+}
+
+module_init(kprobe_init)
+module_exit(kprobe_exit)
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Michael Vetter <mvetter@suse.com>");
+MODULE_DESCRIPTION("Livepatch test: kprobe function");