1 // Copyright 2017 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // The bug happened like this: 6 // 1) The main binary adds an itab for *json.UnsupportedValueError / error 7 // (concrete type / interface type). This itab goes in hash bucket 0x111. 8 // 2) The plugin adds that same itab again. That makes a cycle in the itab 9 // chain rooted at hash bucket 0x111. 10 // 3) The main binary then asks for the itab for *dynamodbstreamsevt.Event / 11 // json.Unmarshaler. This itab happens to also live in bucket 0x111. 12 // The lookup code goes into an infinite loop searching for this itab. 13 // The code is carefully crafted so that the two itabs are both from the 14 // same bucket, and so that the second itab doesn't exist in 15 // the itab hashmap yet (so the entire linked list must be searched). 16 package main 17 18 import ( 19 "encoding/json" 20 "issue18676/dynamodbstreamsevt" 21 "plugin" 22 ) 23 24 func main() { 25 plugin.Open("plugin.so") 26 27 var x interface{} = (*dynamodbstreamsevt.Event)(nil) 28 if _, ok := x.(json.Unmarshaler); !ok { 29 println("something") 30 } 31 } 32
