[PATCH v3 2/3] selftests: livepatch: save and restore kprobe state

From: Michael Vetter
Date: Fri Sep 20 2024 - 07:57:37 EST


Save the state of /sys/kernel/livepatch/debug/kprobes/enabled
during setup_config() and restore it during cleanup().

This is in preparation for a future commit that will add a test
that should confirm that we cannot livepatch a kprobed function
if that kprobe has a post handler.

Signed-off-by: Michael Vetter <mvetter@xxxxxxxx>
---
tools/testing/selftests/livepatch/functions.sh | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/livepatch/functions.sh b/tools/testing/selftests/livepatch/functions.sh
index 50361fceff06..6684c01c0567 100644
--- a/tools/testing/selftests/livepatch/functions.sh
+++ b/tools/testing/selftests/livepatch/functions.sh
@@ -6,7 +6,10 @@

MAX_RETRIES=600
RETRY_INTERVAL=".1" # seconds
-SYSFS_KLP_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
@@ -58,6 +61,7 @@ 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)
+ KPROBE_ENABLED=$(cat $SYSFS_KPROBES_DIR/enabled)
}

function pop_config() {
@@ -67,6 +71,9 @@ function pop_config() {
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() {
--
2.46.0