diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index c8d9e76..bfb4538 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -6031,6 +6031,7 @@ static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn
 	}
 
 	if (insn->code == (BPF_JMP | BPF_CALL) &&
+	    insn->src_reg == 0 &&
 	    insn->imm == BPF_FUNC_timer_set_callback) {
 		struct bpf_verifier_state *async_cb;