Most likely the first thing to enable is the CONFIG_EXPERT=y (General setup -> Configure standard kernel features (expert users)) option, which on x86_64 depends on the CONFIG_EMBEDDED=y (General setup -> Embedded system) one (welcome to Kconfig reverse chains hell).
The following options must be enabled for CRIU to work:
- General setup options
CONFIG_CHECKPOINT_RESTORE=y(Checkpoint/restore support)CONFIG_NAMESPACES=y(Namespaces support)CONFIG_UTS_NS=y(Namespaces support -> UTS namespace)CONFIG_IPC_NS=y(Namespaces support -> IPC namespace)CONFIG_PID_NS=y(Namespaces support -> PID namespaces)CONFIG_NET_NS=y(Namespaces support -> Network namespace)CONFIG_FHANDLE=y(Open by fhandle syscalls)CONFIG_EVENTFD=y(Enable eventfd() system call)CONFIG_EPOLL=y(Enable eventpoll support)
- Networking support -> Networking options options for sock-diag subsystem
CONFIG_UNIX_DIAG=y(Unix domain sockets -> UNIX: socket monitoring interface)CONFIG_INET_DIAG=y(TCP/IP networking -> INET: socket monitoring interface)CONFIG_INET_UDP_DIAG=y(TCP/IP networking -> INET: socket monitoring interface -> UDP: socket monitoring interface)CONFIG_PACKET_DIAG=y(Packet socket -> Packet: sockets monitoring interface)CONFIG_NETLINK_DIAG=y(Netlink socket -> Netlink: sockets monitoring interface)
CONFIG_NETFILTER_XT_MARK=y(Networking support -> Networking options -> Network packet filtering framework (Netfilter) -> Core Netfilter Configuration -> Netfilter Xtables support (required for ip_tables) -> nfmark target and match support)
Other options not required by CRIU, but C/R supported (ZDTM test suite may fail without them):
CONFIG_INOTIFY_USER=y(File systems -> Inotify support for userspace)CONFIG_FANOTIFY=y(File systems -> Filesystem wide access notification)CONFIG_MEMCG=y(General setup -> Control Group support -> Memory controller)CONFIG_CGROUP_DEVICE=y(General setup -> Control Group support -> Device controller)CONFIG_MACVLAN=y(Device Drivers -> Network device support -> Network core driver support -> MAC-VLAN support)CONFIG_BRIDGE=y(Networking support -> Networking options -> 802.1d Ethernet Bridging)CONFIG_BINFMT_MISC=y(Userspace binary formats -> Kernel support for MISC binaries)CONFIG_IA32_EMULATION=y(x86 only) (Executable file formats -> Emulations -> IA32 Emulation)
For some usage scenarios there is an ability to track memory changes and produce incremental dumps. Need to enable the CONFIG_MEM_SOFT_DIRTY=y (optional) (Processor type and features -> Track memory changes).
In the beginning of the project we had our custom kernel, which contained some experimental CRIU related patches. Nowadays this is almost not used.