diff --git a/linux_tools/bpf_exp.y b/linux_tools/bpf_exp.y
index 747be4d..49ecd16 100644
--- a/linux_tools/bpf_exp.y
+++ b/linux_tools/bpf_exp.y
@@ -35,6 +35,7 @@
 enum jmp_type { JTL, JFL, JKL };
 
 extern FILE *yyin;
+extern int yylineno;
 extern int yylex(void);
 extern void yyerror(const char *str);
 
@@ -292,13 +293,13 @@ ldx
 	| OP_LDXB number '*' '(' '[' number ']' '&' number ')' {
 		if ($2 != 4 || $9 != 0xf) {
 			fprintf(stderr, "ldxb offset not supported!\n");
-			exit(0);
+			exit(1);
 		} else {
 			bpf_set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } }
 	| OP_LDX number '*' '(' '[' number ']' '&' number ')' {
 		if ($2 != 4 || $9 != 0xf) {
 			fprintf(stderr, "ldxb offset not supported!\n");
-			exit(0);
+			exit(1);
 		} else {
 			bpf_set_curr_instr(BPF_LDX | BPF_MSH | BPF_B, 0, 0, $6); } }
 	;
@@ -579,7 +580,7 @@ static void bpf_assert_max(void)
 {
 	if (curr_instr >= BPF_MAXINSNS) {
 		fprintf(stderr, "only max %u insns allowed!\n", BPF_MAXINSNS);
-		exit(0);
+		exit(1);
 	}
 }
 
@@ -629,7 +630,7 @@ static int bpf_find_insns_offset(const char *label)
 
 	if (ret == -ENOENT) {
 		fprintf(stderr, "no such label \'%s\'!\n", label);
-		exit(0);
+		exit(1);
 	}
 
 	return ret;
@@ -652,6 +653,18 @@ static void bpf_reduce_k_jumps(void)
 	}
 }
 
+static uint8_t bpf_encode_jt_jf_offset(int off, int i)
+{
+	int delta = off - i - 1;
+
+	if (delta < 0 || delta > 255) {
+		fprintf(stderr, "error: insn #%d jumps to insn #%d, "
+				"which is out of range\n", i, off);
+		exit(1);
+	}
+	return (uint8_t) delta;
+}
+
 static void bpf_reduce_jt_jumps(void)
 {
 	int i;
@@ -659,7 +672,7 @@ static void bpf_reduce_jt_jumps(void)
 	for (i = 0; i < curr_instr; i++) {
 		if (labels_jt[i]) {
 			int off = bpf_find_insns_offset(labels_jt[i]);
-			out[i].jt = (uint8_t) (off - i -1);
+			out[i].jt = bpf_encode_jt_jf_offset(off, i);
 		}
 	}
 }
@@ -671,7 +684,7 @@ static void bpf_reduce_jf_jumps(void)
 	for (i = 0; i < curr_instr; i++) {
 		if (labels_jf[i]) {
 			int off = bpf_find_insns_offset(labels_jf[i]);
-			out[i].jf = (uint8_t) (off - i - 1);
+			out[i].jf = bpf_encode_jt_jf_offset(off, i);
 		}
 	}
 }
@@ -758,5 +771,6 @@ void bpf_asm_compile(FILE *fp, bool cstyle)
 
 void yyerror(const char *str)
 {
+	fprintf(stderr, "error: %s at line %d\n", str, yylineno);
 	exit(1);
 }