diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index a1349ca6466961d8eef510a9d4de9391c0f7c5d1..e163b7b64c86cdac7111a53cc641e41a85fc00bb 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -246,6 +246,7 @@ check_syscall_nr:
 	 */
 	li t1, -1
 	beq a7, t1, ret_from_syscall_rejected
+	blt a7, t1, 1f
 	/* Call syscall */
 	la s0, sys_call_table
 	slli t0, a7, RISCV_LGPTR