bpf: make bpf_copy_from_user_task() gpl only

access_process_vm() is exported by EXPORT_SYMBOL_GPL().
Signed-off-by: Kenta Tada <Kenta.Tada@sony.com>
Link: https://lore.kernel.org/r/20220128170906.21154-1-Kenta.Tada@sony.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

kernel/bpf/helpers.c

@@ -695,7 +695,7 @@ BPF_CALL_5(bpf_copy_from_user_task, void *, dst, u32, size,
 
 const struct bpf_func_proto bpf_copy_from_user_task_proto = {
 	.func		= bpf_copy_from_user_task,
-	.gpl_only	= false,
+	.gpl_only	= true,
 	.ret_type	= RET_INTEGER,
 	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,
 	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,