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https://github.com/golang/go
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bdb480fd62
Currently, the statement:
go g(uintptr(f()))
gets rewritten into:
tmp := f()
newproc(8, g, uintptr(tmp))
runtime.KeepAlive(tmp)
which doesn't guarantee that tmp is still alive by time the g call is
scheduled to run.
This CL fixes the issue, by wrapping g call in a closure:
go func(p unsafe.Pointer) {
g(uintptr(p))
}(f())
then this will be rewritten into:
tmp := f()
go func(p unsafe.Pointer) {
g(uintptr(p))
runtime.KeepAlive(p)
}(tmp)
runtime.KeepAlive(tmp) // superfluous, but harmless
So the unsafe.Pointer p will be kept alive at the time g call runs.
Updates #24491
Change-Id: Ic10821251cbb1b0073daec92b82a866c6ebaf567
Reviewed-on: https://go-review.googlesource.com/c/go/+/253457
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
46 lines
799 B
Go
46 lines
799 B
Go
// run
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// Copyright 2020 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// This test makes sure unsafe-uintptr arguments are handled correctly.
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package main
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import (
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"runtime"
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"unsafe"
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)
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var done = make(chan bool, 1)
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func setup() unsafe.Pointer {
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s := "ok"
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runtime.SetFinalizer(&s, func(p *string) { *p = "FAIL" })
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return unsafe.Pointer(&s)
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}
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//go:noinline
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//go:uintptrescapes
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func test(s string, p uintptr) {
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runtime.GC()
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if *(*string)(unsafe.Pointer(p)) != "ok" {
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panic(s + " return unexpected result")
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}
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done <- true
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}
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func main() {
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test("normal", uintptr(setup()))
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<-done
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go test("go", uintptr(setup()))
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<-done
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func() {
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defer test("defer", uintptr(setup()))
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}()
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<-done
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}
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