diff options
| -rw-r--r-- | misc/cgo/testplugin/plugin_test.go | 28 | ||||
| -rw-r--r-- | misc/cgo/testplugin/testdata/forkexec/main.go | 30 | ||||
| -rw-r--r-- | src/cmd/link/internal/ld/lib.go | 5 |
3 files changed, 62 insertions, 1 deletions
diff --git a/misc/cgo/testplugin/plugin_test.go b/misc/cgo/testplugin/plugin_test.go index 8869528015..7b4df3f8ed 100644 --- a/misc/cgo/testplugin/plugin_test.go +++ b/misc/cgo/testplugin/plugin_test.go @@ -216,3 +216,31 @@ func TestIssue44956(t *testing.T) { goCmd(t, "build", "-o", "issue44956.exe", "./issue44956/main.go") run(t, "./issue44956.exe") } + +func TestForkExec(t *testing.T) { + // Issue 38824: importing the plugin package causes it hang in forkExec on darwin. + + t.Parallel() + goCmd(t, "build", "-o", "forkexec.exe", "./forkexec/main.go") + + var cmd *exec.Cmd + done := make(chan int, 1) + + go func() { + for i := 0; i < 100; i++ { + cmd = exec.Command("./forkexec.exe", "1") + err := cmd.Run() + if err != nil { + t.Errorf("running command failed: %v", err) + break + } + } + done <- 1 + }() + select { + case <-done: + case <-time.After(5 * time.Minute): + cmd.Process.Kill() + t.Fatalf("subprocess hang") + } +} diff --git a/misc/cgo/testplugin/testdata/forkexec/main.go b/misc/cgo/testplugin/testdata/forkexec/main.go new file mode 100644 index 0000000000..3169ff5f04 --- /dev/null +++ b/misc/cgo/testplugin/testdata/forkexec/main.go @@ -0,0 +1,30 @@ +// Copyright 2021 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" + "os/exec" + _ "plugin" + "sync" +) + +func main() { + if os.Args[1] != "1" { + return + } + + var wg sync.WaitGroup + for i := 0; i < 8; i++ { + wg.Add(1) + go func() { + defer wg.Done() + // does not matter what we exec, just exec itself + cmd := exec.Command("./forkexec.exe", "0") + cmd.Run() + }() + } + wg.Wait() +} diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go index 18db567041..d56a51e375 100644 --- a/src/cmd/link/internal/ld/lib.go +++ b/src/cmd/link/internal/ld/lib.go @@ -1269,7 +1269,10 @@ func (ctxt *Link) hostlink() { if ctxt.DynlinkingGo() && objabi.GOOS != "ios" { // -flat_namespace is deprecated on iOS. // It is useful for supporting plugins. We don't support plugins on iOS. - argv = append(argv, "-Wl,-flat_namespace") + // -flat_namespace may cause the dynamic linker to hang at forkExec when + // resolving a lazy binding. See issue 38824. + // Force eager resolution to work around. + argv = append(argv, "-Wl,-flat_namespace", "-Wl,-bind_at_load") } if !combineDwarf { argv = append(argv, "-Wl,-S") // suppress STAB (symbolic debugging) symbols |