5 files changed, 231 insertions, 0 deletions
diff --git a/src/runtime/testdata/testprognet/main.go b/src/runtime/testdata/testprognet/main.go
new file mode 100644
index 0000000..ae491a2
--- /dev/null
+++ b/src/runtime/testdata/testprognet/main.go
@@ -0,0 +1,35 @@
+// Copyright 2015 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 "os"
+
+var cmds = map[string]func(){}
+
+func register(name string, f func()) {
+	if cmds[name] != nil {
+		panic("duplicate registration: " + name)
+	}
+	cmds[name] = f
+}
+
+func registerInit(name string, f func()) {
+	if len(os.Args) >= 2 && os.Args[1] == name {
+		f()
+	}
+}
+
+func main() {
+	if len(os.Args) < 2 {
+		println("usage: " + os.Args[0] + " name-of-test")
+		return
+	}
+	f := cmds[os.Args[1]]
+	if f == nil {
+		println("unknown function: " + os.Args[1])
+		return
+	}
+	f()
+}
diff --git a/src/runtime/testdata/testprognet/net.go b/src/runtime/testdata/testprognet/net.go
new file mode 100644
index 0000000..714b101
--- /dev/null
+++ b/src/runtime/testdata/testprognet/net.go
@@ -0,0 +1,29 @@
+// Copyright 2015 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 (
+	"fmt"
+	"net"
+)
+
+func init() {
+	registerInit("NetpollDeadlock", NetpollDeadlockInit)
+	register("NetpollDeadlock", NetpollDeadlock)
+}
+
+func NetpollDeadlockInit() {
+	fmt.Println("dialing")
+	c, err := net.Dial("tcp", "localhost:14356")
+	if err == nil {
+		c.Close()
+	} else {
+		fmt.Println("error: ", err)
+	}
+}
+
+func NetpollDeadlock() {
+	fmt.Println("done")
+}
diff --git a/src/runtime/testdata/testprognet/signal.go b/src/runtime/testdata/testprognet/signal.go
new file mode 100644
index 0000000..dfa2e10
--- /dev/null
+++ b/src/runtime/testdata/testprognet/signal.go
@@ -0,0 +1,27 @@
+// Copyright 2016 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.
+
+//go:build !windows && !plan9
+// +build !windows,!plan9
+
+// This is in testprognet instead of testprog because testprog
+// must not import anything (like net, but also like os/signal)
+// that kicks off background goroutines during init.
+
+package main
+
+import (
+	"os/signal"
+	"syscall"
+)
+
+func init() {
+	register("SignalIgnoreSIGTRAP", SignalIgnoreSIGTRAP)
+}
+
+func SignalIgnoreSIGTRAP() {
+	signal.Ignore(syscall.SIGTRAP)
+	syscall.Kill(syscall.Getpid(), syscall.SIGTRAP)
+	println("OK")
+}
diff --git a/src/runtime/testdata/testprognet/signalexec.go b/src/runtime/testdata/testprognet/signalexec.go
new file mode 100644
index 0000000..62ebce7
--- /dev/null
+++ b/src/runtime/testdata/testprognet/signalexec.go
@@ -0,0 +1,71 @@
+// 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.
+
+//go:build darwin || dragonfly || freebsd || linux || netbsd || openbsd
+// +build darwin dragonfly freebsd linux netbsd openbsd
+
+// This is in testprognet instead of testprog because testprog
+// must not import anything (like net, but also like os/signal)
+// that kicks off background goroutines during init.
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"os/signal"
+	"sync"
+	"syscall"
+	"time"
+)
+
+func init() {
+	register("SignalDuringExec", SignalDuringExec)
+	register("Nop", Nop)
+}
+
+func SignalDuringExec() {
+	pgrp := syscall.Getpgrp()
+
+	const tries = 10
+
+	var wg sync.WaitGroup
+	c := make(chan os.Signal, tries)
+	signal.Notify(c, syscall.SIGWINCH)
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		for range c {
+		}
+	}()
+
+	for i := 0; i < tries; i++ {
+		time.Sleep(time.Microsecond)
+		wg.Add(2)
+		go func() {
+			defer wg.Done()
+			cmd := exec.Command(os.Args[0], "Nop")
+			cmd.Stdout = os.Stdout
+			cmd.Stderr = os.Stderr
+			if err := cmd.Run(); err != nil {
+				fmt.Printf("Start failed: %v", err)
+			}
+		}()
+		go func() {
+			defer wg.Done()
+			syscall.Kill(-pgrp, syscall.SIGWINCH)
+		}()
+	}
+
+	signal.Stop(c)
+	close(c)
+	wg.Wait()
+
+	fmt.Println("OK")
+}
+
+func Nop() {
+	// This is just for SignalDuringExec.
+}
diff --git a/src/runtime/testdata/testprognet/waiters.go b/src/runtime/testdata/testprognet/waiters.go
new file mode 100644
index 0000000..a65c40b
--- /dev/null
+++ b/src/runtime/testdata/testprognet/waiters.go
@@ -0,0 +1,69 @@
+// Copyright 2023 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 (
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"runtime/internal/atomic"
+	"sync"
+	"time"
+	_ "unsafe" // for go:linkname
+)
+
+// The bug is that netpollWaiters increases monotonically.
+// This doesn't cause a problem until it overflows.
+// Use linkname to see the value.
+//
+//go:linkname netpollWaiters runtime.netpollWaiters
+var netpollWaiters atomic.Uint32
+
+func init() {
+	register("NetpollWaiters", NetpollWaiters)
+}
+
+func NetpollWaiters() {
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		conn, err := listener.Accept()
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer conn.Close()
+		if _, err := io.Copy(io.Discard, conn); err != nil {
+			log.Fatal(err)
+		}
+	}()
+
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		conn, err := net.Dial("tcp", listener.Addr().String())
+		if err != nil {
+			log.Fatal(err)
+		}
+		defer conn.Close()
+		for i := 0; i < 10; i++ {
+			fmt.Fprintf(conn, "%d\n", i)
+			time.Sleep(time.Millisecond)
+		}
+	}()
+
+	wg.Wait()
+	if v := netpollWaiters.Load(); v != 0 {
+		log.Fatalf("current waiters %v", v)
+	}
+
+	fmt.Println("OK")
+}