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https://github.com/golang/go
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8f1e2d4ef7
If we run 'go test ./...' in the misc module, we don't want to see errors for these standalone files. We could instead add +ignore tags to each file individually, but this is exactly what a testdata directory is for. Updates #30228 Change-Id: I7047ad888dd6aff701f5982d58b6a79f6a487c58 Reviewed-on: https://go-review.googlesource.com/c/163417 Run-TryBot: Bryan C. Mills <bcmills@google.com> Reviewed-by: Jay Conrod <jayconrod@google.com>
73 lines
1.4 KiB
Go
73 lines
1.4 KiB
Go
// Copyright 2018 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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package main
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// A C function returning a value on the Go stack could leave the Go
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// stack marked as uninitialized, potentially causing a later error
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// when the stack is used for something else. Issue 26209.
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/*
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#cgo LDFLAGS: -fsanitize=memory
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#cgo CPPFLAGS: -fsanitize=memory
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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typedef struct {
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uintptr_t a[20];
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} S;
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S f() {
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S *p;
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p = (S *)(malloc(sizeof(S)));
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p->a[0] = 0;
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return *p;
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}
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*/
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import "C"
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// allocateStack extends the stack so that stack copying doesn't
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// confuse the msan data structures.
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//go:noinline
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func allocateStack(i int) int {
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if i == 0 {
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return i
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}
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return allocateStack(i - 1)
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}
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// F1 marks a chunk of stack as uninitialized.
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// C.f returns an uninitialized struct on the stack, so msan will mark
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// the stack as uninitialized.
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//go:noinline
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func F1() uintptr {
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s := C.f()
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return uintptr(s.a[0])
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}
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// F2 allocates a struct on the stack and converts it to an empty interface,
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// which will call msanread and see that the data appears uninitialized.
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//go:noinline
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func F2() interface{} {
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return C.S{}
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}
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func poisonStack(i int) int {
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if i == 0 {
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return int(F1())
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}
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F1()
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r := poisonStack(i - 1)
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F2()
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return r
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}
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func main() {
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allocateStack(16384)
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poisonStack(128)
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}
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