File size: 2,340 Bytes
e36aeda | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 | // Copyright 2024 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
import (
"internal/asan"
"internal/race"
"runtime"
"runtime/debug"
"unsafe"
)
func init() {
register("DetectFinalizerAndCleanupLeaks", DetectFinalizerAndCleanupLeaks)
}
type tiny uint8
var tinySink *tiny
// Intended to be run only with `GODEBUG=checkfinalizers=1`.
func DetectFinalizerAndCleanupLeaks() {
type T *int
defer debug.SetGCPercent(debug.SetGCPercent(-1))
// Leak a cleanup.
cLeak := new(T)
// Use an extra closure to avoid the simple
// checking done by AddCleanup.
var closeOverCLeak func(int)
closeOverCLeak = func(x int) {
// Use recursion to avoid inlining.
if x <= 0 {
**cLeak = x
} else {
closeOverCLeak(x - 1)
}
}
runtime.AddCleanup(cLeak, func(x int) {
closeOverCLeak(x)
}, int(0))
// Have a regular cleanup to make sure it doesn't trip the detector.
cNoLeak := new(T)
runtime.AddCleanup(cNoLeak, func(_ int) {}, int(0))
// Like closeOverCLeak.
var closeOverCNoLeak func(int)
closeOverCNoLeak = func(x int) {
if x <= 0 {
**cNoLeak = x
} else {
closeOverCNoLeak(x - 1)
}
}
// Add a cleanup that only temporarily leaks cNoLeak.
runtime.AddCleanup(cNoLeak, func(x int) {
closeOverCNoLeak(x)
}, int(0)).Stop()
if !asan.Enabled && !race.Enabled {
// Ensure we create an allocation into a tiny block that shares space among several values.
//
// Don't do this with ASAN and in race mode, where the tiny allocator is disabled.
// We might just loop forever here in that case.
var ctLeak *tiny
for {
tinySink = ctLeak
ctLeak = new(tiny)
*ctLeak = tiny(55)
// Make sure the address is an odd value. This is sufficient to
// be certain that we're sharing a block with another value and
// trip the detector.
if uintptr(unsafe.Pointer(ctLeak))%2 != 0 {
break
}
}
runtime.AddCleanup(ctLeak, func(_ struct{}) {}, struct{}{})
}
// Leak a finalizer.
fLeak := new(T)
runtime.SetFinalizer(fLeak, func(_ *T) {
**fLeak = 12
})
// Have a regular finalizer to make sure it doesn't trip the detector.
fNoLeak := new(T)
runtime.SetFinalizer(fNoLeak, func(x *T) {
**x = 51
})
// runtime.GC here should crash.
runtime.GC()
println("OK")
}
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