sched_ext: define missing cfi stubs for sched_ext

`__bpf_ops_sched_ext_ops` was missing the initialization of some struct
attributes. With

https://lore.kernel.org/all/[e-mail]/

every single attributes need to be initialized programs (like scx_layered)
will fail to load.

05:26:48 [INFO] libbpf: struct_ops layered: member cgroup_init not found in kernel, skipping it as it's set to zero
05:26:48 [INFO] libbpf: struct_ops layered: member cgroup_exit not found in kernel, skipping it as it's set to zero
05:26:48 [INFO] libbpf: struct_ops layered: member cgroup_prep_move not found in kernel, skipping it as it's set to zero
05:26:48 [INFO] libbpf: struct_ops layered: member cgroup_move not found in kernel, skipping it as it's set to zero
05:26:48 [INFO] libbpf: struct_ops layered: member cgroup_cancel_move not found in kernel, skipping it as it's set to zero
05:26:48 [INFO] libbpf: struct_ops layered: member cgroup_set_weight not found in kernel, skipping it as it's set to zero
05:26:48 [WARN] libbpf: prog 'layered_dump': BPF program load failed: unknown error (-524)
05:26:48 [WARN] libbpf: prog 'layered_dump': -- BEGIN PROG LOAD LOG --
attach to unsupported member dump of struct sched_ext_ops
processed 0 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
-- END PROG LOAD LOG --
05:26:48 [WARN] libbpf: prog 'layered_dump': failed to load: -524
05:26:48 [WARN] libbpf: failed to load object 'bpf_bpf'
05:26:48 [WARN] libbpf: failed to load BPF skeleton 'bpf_bpf': -524
Error: Failed to load BPF program

Signed-off-by: Manu Bretelle <[e-mail]>
Signed-off-by: Tejun Heo <[e-mail]>

kernel/sched/ext.c

···
 static void cpu_offline_stub(s32 cpu) {}
 static s32 init_stub(void) { return -EINVAL; }
 static void exit_stub(struct scx_exit_info *info) {}
+static void dump_stub(struct scx_dump_ctx *ctx) {}
+static void dump_cpu_stub(struct scx_dump_ctx *ctx, s32 cpu, bool idle) {}
+static void dump_task_stub(struct scx_dump_ctx *ctx, struct task_struct *p) {}
 
 static struct sched_ext_ops __bpf_ops_sched_ext_ops = {
 	.select_cpu = select_cpu_stub,
···
 	.cpu_offline = cpu_offline_stub,
 	.init = init_stub,
 	.exit = exit_stub,
+	.dump = dump_stub,
+	.dump_cpu = dump_cpu_stub,
+	.dump_task = dump_task_stub,
 };
 
 static struct bpf_struct_ops bpf_sched_ext_ops = {