Implement kexec reboot support for SSH mode

bisect.conf

@@ -21,7 +21,7 @@ TEST_STRATEGY="panic"
 
 # REBOOT_STRATEGY: 'reboot' or 'kexec'
 # 'reboot': Performs a full, normal system reboot.
-# 'kexec': Uses 'kexec -e' for a faster reboot (requires kexec to be configured).
+# 'kexec': Uses 'systemctl kexec' for a faster reboot (requires kexec to be configured).
 REBOOT_STRATEGY="reboot"
 
 # === Git Repository (for INSTALL_STRATEGY="git" or auto mode) ===

criu-daemon.sh

@@ -100,7 +100,7 @@ handle_checkpoint() {
 	rm -f "$CHECKPOINT_SIGNAL"
 
 	log "Received checkpoint+panic request"
-	if ! grep -e sysrq-trigger -e reboot "$_cmd_file"; then
+	if ! grep -e sysrq-trigger -e reboot -e 'systemctl kexec' "$_cmd_file"; then
 		return 1
 	fi
 	if do_checkpoint; then

handlers/install_handler.sh

@@ -211,7 +211,7 @@ install_from_rpm() {
 		fi
 	done
 
-	if ! run_cmd dnf install -y "${rpms_to_install[@]}" >"/var/log/install.log" 2>&1; then do_abort "RPM install failed."; fi
+	if ! run_cmd dnf install -y "${rpms_to_install[@]}" ">/var/log/install.log" '2>&1'; then do_abort "RPM install failed."; fi
 	TESTED_KERNEL="$release"
 	[[ $_kernel_name_prefix == kernel-rt ]] && TESTED_KERNEL+=+rt
 }

handlers/reboot_handler.sh

@@ -33,8 +33,11 @@ do_full_reboot() {
 }
 
 do_kexec_reboot() {
-	log "Strategy: kexec not supported with CRIU checkpointing, using full reboot..."
-	# kexec bypasses the normal boot process, which would prevent the CRIU daemon
-	# from properly restoring the process. Fall back to full reboot.
-	do_full_reboot
+	log "Strategy: Performing kexec reboot (fast reboot)"
+	if ! kexec_load_kernel "$TESTED_KERNEL"; then
+		log "Falling back to full reboot"
+		do_full_reboot
+		return
+	fi
+	kab_kexec
 }

lib.sh

@@ -83,6 +83,8 @@ signal_checkpoint() {
 		printf "sync\n %s" "${_reboot_cmd}" >"$CHECKPOINT_SIGNAL"
 	elif [[ $1 == panic ]]; then
 		printf "sync\n echo 1 > /proc/sys/kernel/sysrq\n echo c > /proc/sysrq-trigger" >"$CHECKPOINT_SIGNAL"
+	elif [[ $1 == kexec ]]; then
+		printf "sync\n systemctl kexec" >"$CHECKPOINT_SIGNAL"
 	fi
 
 	# Wait for the daemon to process our request and reboot/panic the system
@@ -155,6 +157,36 @@ reboot_and_wait() {
 	done
 }
 
+kexec_load_kernel() {
+	local kernel_release="$1"
+	local vmlinuz="/boot/vmlinuz-${kernel_release}"
+	local initramfs="/boot/initramfs-${kernel_release}.img"
+
+	if ! run_cmd test -f "$vmlinuz"; then
+		log "ERROR: Kernel not found: $vmlinuz"
+		return 1
+	fi
+	if ! run_cmd test -f "$initramfs"; then
+		log "ERROR: Initramfs not found: $initramfs"
+		return 1
+	fi
+
+	log "Loading kernel ${kernel_release} into kexec"
+	if ! run_cmd kexec -l "$vmlinuz" --initrd="$initramfs" --reuse-cmdline; then
+		log "ERROR: Failed to load kernel into kexec"
+		return 1
+	fi
+	log "Kernel loaded into kexec successfully"
+}
+
+kab_kexec() {
+	if [[ -z $KAB_TEST_HOST ]]; then
+		signal_checkpoint "kexec"
+	else
+		reboot_and_wait systemctl kexec
+	fi
+}
+
 prepare_reboot() {
 	# try to reboot to current EFI bootloader entry next time
 	run_cmd command -v rstrnt-prepare-reboot &>/dev/null && run_cmd rstrnt-prepare-reboot >/dev/null
@@ -421,6 +453,15 @@ END
 }
 
 setup_kdump() {
+	if [[ "$REBOOT_STRATEGY" == "kexec" ]]; then
+		if ! run_cmd command -v kexec &>/dev/null; then
+			if ! run_cmd dnf install kexec-tools -yq; then
+				log "Failed to install kexec-tools!"
+				exit 1
+			fi
+		fi
+	fi
+
 	if [[ "$TEST_STRATEGY" == "panic" ]]; then
 		if ! run_cmd command -v kdumpctl &>/dev/null; then
 			if ! run_cmd dnf install kdump-utils -yq && ! run_cmd dnf install kexec-tools -yq; then

tests/kab_criu/test.sh

@@ -52,7 +52,7 @@ done
 cat <<END | ssh_cmd "cat >$CONF_FILE"
 INSTALL_STRATEGY="rpm"
 TEST_STRATEGY="panic"
-REBOOT_STRATEGY=
+REBOOT_STRATEGY="kexec"
 RPM_CACHE_DIR="/var/cache/kdump-bisect-rpms"
 BAD_COMMIT=$BAD_COMMIT
 REPRODUCER_SCRIPT=$TEST_SCRIPT

tests/kab_ssh/test.sh

@@ -28,7 +28,7 @@ if echo "${CLIENTS}" | grep -qi "${HOSTNAME}"; then
 	cat <<END >"$CONF_FILE"
 INSTALL_STRATEGY="rpm"
 TEST_STRATEGY="panic"
-REBOOT_STRATEGY=
+REBOOT_STRATEGY="kexec"
 RPM_CACHE_DIR="/var/cache/kdump-bisect-rpms"
 GOOD_COMMIT=$GOOD_COMMIT
 BAD_COMMIT=$BAD_COMMIT