bradfitz

(Claude Code; Opus 4.6)

Windows Stack Memory Corruption Investigation

Summary

Runtime stack memory corruption on Windows amd64 causes a DEP violation (Exception 0xc0000005 code 0x8) when a goroutine jumps to a corrupted return address. The corruption always overwrites the high 32 bits of a return address, replacing a valid code pointer (e.g. 0x00007ff6XXXXXXXX) with a value whose high 32 bits are a

bradfitz

set -eu

mkdir -p /tmp/foo && cd /tmp/foo

git init
mkdir testing
touch testing.md testing/empty-dir
git add testing testing.md
git commit -m 'foo'
git cat-file -p HEAD^{tree}

bradfitz

package main

import (
	"bytes"
	"flag"
	"io/fs"
	"log"
	"os"
	"path/filepath"
	"strings"

bradfitz

diff --git a/src/unique/handle.go b/src/unique/handle.go
index abc620f60f..95395a6b85 100644
--- a/src/unique/handle.go
+++ b/src/unique/handle.go
@@ -10,6 +10,7 @@ import (
 	"internal/weak"
 	"runtime"
 	"sync"
+	"sync/atomic"
 	_ "unsafe"

bradfitz

diff --git a/src/unique/handle.go b/src/unique/handle.go
index 520ab70f8c..113eb90fd9 100644
--- a/src/unique/handle.go
+++ b/src/unique/handle.go
@@ -9,6 +9,8 @@ import (
 	isync "internal/sync"
 	"runtime"
 	"sync"
+	"sync/atomic"
+	"time"

bradfitz

{
    "Hostname": "tskrazy",
    "Update": {
        "Hostname": "192.168.64.5",
        "HTTPPassword": "xxxxx"
    },
    "Packages": [
        "github.com/gokrazy/fbstatus",
        "github.com/gokrazy/hello",
        "github.com/gokrazy/serial-busybox",

bradfitz

=== RUN   TestRepoStress
=== RUN   TestRepoStress/normal
    repo_test.go:61: after 10000, +131.322375ms
    repo_test.go:61: after 20000, +145.117792ms
    repo_test.go:61: after 30000, +157.902291ms
    repo_test.go:61: after 40000, +156.549084ms
    repo_test.go:61: after 50000, +155.986ms
    repo_test.go:61: after 60000, +155.7875ms
    repo_test.go:61: after 70000, +157.752625ms
    repo_test.go:61: after 80000, +163.210541ms

bradfitz

package main

import (
        "io"
        "log"
        "net"
        "net/http"
        "os"
)

bradfitz

package main

import (
        "bytes"
        "crypto/tls"
        "crypto/x509"
        "io/ioutil"
        "log"
        "net/http"

bradfitz

############# free

               total        used        free      shared  buff/cache   available
Mem:        98774364     2635644    95638772       29756      499948    95242576
Swap:        7602172           0     7602172

############# lspci

00:00.0 Host bridge: Intel Corporation Xeon E7 v3/Xeon E5 v3/Core i7 DMI2 (rev 02)