pkg/ifuzz: add a regression test for x86 decoding

For the following fix to x86 instruction decoding, add a regression test
reported by syzbot.

1 files changed, 35 insertions, 0 deletions

diff --git a/pkg/ifuzz/x86_test.go b/pkg/ifuzz/x86_test.go
new file mode 100644
index 000000000..e9ee25c20
--- /dev/null
+++ b/pkg/ifuzz/x86_test.go
@@ -0,0 +1,35 @@
+// Copyright 2024 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package ifuzz
+
+import (
+	"encoding/hex"
+	"strings"
+	"testing"
+
+	"github.com/google/syzkaller/pkg/ifuzz/iset"
+)
+
+// Regression test for x86 instruction decoding.
+// nolint: lll
+func TestDecodeRegression(t *testing.T) {
+	testData := []string{
+		"46 f7 25 04 49 a3 2c b9 14 01 01 c0 b8 c3 de 66 3f ba 1f 38 8b 0f 0f 30 2e 6e 2e 74 1c 0f 01 30 b9 80 00 00 c0 0f 32 35 00 08 00 00 0f 30 d9 be 45 00 00 00 c7 44 24 00 0b 00 00 00 c7 44 24 02 0e ff ff ff ff 2c 24 c4 23 e9 6c 6e b9 d3",
+	}
+	insnset := iset.Arches[ArchX86]
+	for _, str := range testData {
+		text, err := hex.DecodeString(strings.ReplaceAll(str, " ", ""))
+		if err != nil {
+			t.Fatalf("invalid hex string")
+		}
+		for len(text) != 0 {
+			size, err := insnset.Decode(iset.ModeLong64, text)
+			if size == 0 || err != nil {
+				t.Errorf("failed to decode text: % x", text)
+				break
+			}
+			text = text[size:]
+		}
+	}
+}