96 lines
1.8 KiB
Go
96 lines
1.8 KiB
Go
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// Copyright 2020 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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// +build !plan9,!windows
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package main
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// This is for issue #42207.
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// During a call to needm we could get a SIGCHLD signal
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// which would itself call needm, causing a deadlock.
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/*
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#include <signal.h>
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#include <pthread.h>
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#include <sched.h>
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#include <unistd.h>
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extern void GoNeedM();
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#define SIGNALERS 10
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static void* needmSignalThread(void* p) {
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pthread_t* pt = (pthread_t*)(p);
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int i;
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for (i = 0; i < 100; i++) {
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if (pthread_kill(*pt, SIGCHLD) < 0) {
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return NULL;
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}
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usleep(1);
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}
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return NULL;
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}
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// We don't need many calls, as the deadlock is only likely
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// to occur the first couple of times that needm is called.
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// After that there will likely be an extra M available.
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#define CALLS 10
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static void* needmCallbackThread(void* p) {
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int i;
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for (i = 0; i < SIGNALERS; i++) {
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sched_yield(); // Help the signal threads get started.
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}
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for (i = 0; i < CALLS; i++) {
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GoNeedM();
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}
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return NULL;
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}
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static void runNeedmSignalThread() {
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int i;
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pthread_t caller;
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pthread_t s[SIGNALERS];
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pthread_create(&caller, NULL, needmCallbackThread, NULL);
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for (i = 0; i < SIGNALERS; i++) {
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pthread_create(&s[i], NULL, needmSignalThread, &caller);
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}
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for (i = 0; i < SIGNALERS; i++) {
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pthread_join(s[i], NULL);
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}
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pthread_join(caller, NULL);
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}
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*/
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import "C"
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import (
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"fmt"
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"os"
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"time"
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)
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func init() {
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register("NeedmDeadlock", NeedmDeadlock)
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}
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//export GoNeedM
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func GoNeedM() {
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}
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func NeedmDeadlock() {
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// The failure symptom is that the program hangs because of a
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// deadlock in needm, so set an alarm.
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go func() {
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time.Sleep(5 * time.Second)
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fmt.Println("Hung for 5 seconds")
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os.Exit(1)
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}()
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C.runNeedmSignalThread()
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fmt.Println("OK")
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}
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