diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 0afb4ea..b513659 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -357,6 +357,40 @@
 	list_add(&tl->list_node, &bpf_prog_types);
 }
 
+/* fixup insn->imm field of bpf_call instructions:
+ * if (insn->imm == BPF_FUNC_map_lookup_elem)
+ *      insn->imm = bpf_map_lookup_elem - __bpf_call_base;
+ * else if (insn->imm == BPF_FUNC_map_update_elem)
+ *      insn->imm = bpf_map_update_elem - __bpf_call_base;
+ * else ...
+ *
+ * this function is called after eBPF program passed verification
+ */
+static void fixup_bpf_calls(struct bpf_prog *prog)
+{
+	const struct bpf_func_proto *fn;
+	int i;
+
+	for (i = 0; i < prog->len; i++) {
+		struct bpf_insn *insn = &prog->insnsi[i];
+
+		if (insn->code == (BPF_JMP | BPF_CALL)) {
+			/* we reach here when program has bpf_call instructions
+			 * and it passed bpf_check(), means that
+			 * ops->get_func_proto must have been supplied, check it
+			 */
+			BUG_ON(!prog->aux->ops->get_func_proto);
+
+			fn = prog->aux->ops->get_func_proto(insn->imm);
+			/* all functions that have prototype and verifier allowed
+			 * programs to call them, must be real in-kernel functions
+			 */
+			BUG_ON(!fn->func);
+			insn->imm = fn->func - __bpf_call_base;
+		}
+	}
+}
+
 /* drop refcnt on maps used by eBPF program and free auxilary data */
 static void free_used_maps(struct bpf_prog_aux *aux)
 {
@@ -478,6 +512,9 @@
 	if (err < 0)
 		goto free_used_maps;
 
+	/* fixup BPF_CALL->imm field */
+	fixup_bpf_calls(prog);
+
 	/* eBPF program is ready to be JITed */
 	bpf_prog_select_runtime(prog);