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go/misc/cgo/testsanitizers/msan_test.go
Cherry Zhang 07cba70d57 cmd/compile, runtime: use __msan_memmove for moving data, split msanread to fields
Currently, for data moving, we generate an msanread of the source,
followed by an msanwrite of the destination. msanread checks
the source is initialized.

This has a problem: if the source is an aggregate type containing
alignment paddings, the padding bytes may not be thought as
initialized by MSAN. If we copy the aggregate type by value, if
it counts as a read, MSAN reports using uninitialized data. This
CL changes it to use __msan_memmove for data copying, which tells
MSAN to propagate initialized-ness but not check for it.

Caveat: technically __msan_memmove is not a public API of MSAN,
although the C compiler does generate direct calls to it.

Also, when instrumenting a load of a struct, split the
instrumentation to fields, instead of generating an msanread for
the whole struct. This skips padding bytes, which may not be
considered initialized in MSAN.

Fixes #42820.

Change-Id: Id861c8bbfd94cfcccefcc58eaf9e4eb43b4d85c6
Reviewed-on: https://go-review.googlesource.com/c/go/+/270859
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
2020-12-03 15:40:11 +00:00

58 lines
1.2 KiB
Go

// Copyright 2017 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 sanitizers_test
import (
"strings"
"testing"
)
func TestMSAN(t *testing.T) {
t.Parallel()
requireOvercommit(t)
config := configure("memory")
config.skipIfCSanitizerBroken(t)
mustRun(t, config.goCmd("build", "std"))
cases := []struct {
src string
wantErr bool
}{
{src: "msan.go"},
{src: "msan2.go"},
{src: "msan2_cmsan.go"},
{src: "msan3.go"},
{src: "msan4.go"},
{src: "msan5.go"},
{src: "msan6.go"},
{src: "msan7.go"},
{src: "msan_fail.go", wantErr: true},
}
for _, tc := range cases {
tc := tc
name := strings.TrimSuffix(tc.src, ".go")
t.Run(name, func(t *testing.T) {
t.Parallel()
dir := newTempDir(t)
defer dir.RemoveAll(t)
outPath := dir.Join(name)
mustRun(t, config.goCmd("build", "-o", outPath, srcPath(tc.src)))
cmd := hangProneCmd(outPath)
if tc.wantErr {
out, err := cmd.CombinedOutput()
if err != nil {
return
}
t.Fatalf("%#q exited without error; want MSAN failure\n%s", strings.Join(cmd.Args, " "), out)
}
mustRun(t, cmd)
})
}
}