执行thread_kill时出现分段错误答案

【问题标题】：A segmentation fault occurs when thread_kill is executed执行thread_kill时出现分段错误
【发布时间】：2019-07-04 09:08:03
【问题描述】：

我正在 linux 上用 C 语言开发一个简单的程序，其中有一个线程检查自程序开始以来经过的时间，当它们经过 10 秒时，发送一个结束信号（例如 SIGINT 或 SIGTERM）到主程序，什么应该让它以干净的方式结束。

最后附上C程序。

执行thread_kill调用时，会发生Segmentation fault。

用gdb运行这个程序的结果如下：

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7ffff77f2700 (LWP 25472)]
__pthread_kill (threadid=25466, signo=2) at 
../nptl/sysdeps/unix/sysv/linux/pthread_kill.c:42
42  ../nptl/sysdeps/unix/sysv/linux/pthread_kill.c: No such file or directory.
(gdb) bt
#0  __pthread_kill (threadid=25466, signo=2) at     ../nptl/sysdeps/unix/sysv/linux/pthread_kill.c:42
#1  0x0000000000400a1e in ThreadRoutine (number=1) at program_16b.c:46
#2  0x00007ffff7bc4184 in start_thread (arg=0x7ffff77f2700) at pthread_create.c:312
#3  0x00007ffff78f103d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
(gdb)

我的代码有什么问题？

program.c：

#include <pthread.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <sys/time.h>
#include <signal.h>


#define _REENTRANT

struct timeval begin, end;


void siginthandler(int param)
{
  printf("User has pressed Ctrl + C\n");

}


void *ThreadRoutine(int number)
{
  long microseconds;

  printf ("[thread %d] pthread_self = %d, getpid = %d, getppid = %d\n",
           number, pthread_self(), getpid(), getppid());


  while(1) // loop forever
  {
    printf("thread type 1 (%d) running\n",number);
    if (number == 1)
    {
      gettimeofday(&end, NULL);
      microseconds = (end.tv_sec - begin.tv_sec) * 1000000 + (end.tv_usec - begin.tv_usec);
      printf ("Microseconds from starting time = %ld\n", microseconds);
      if (microseconds >= 10000000)
      {
        printf("Killing parent process after 10 seconds from starting.\n");
        pthread_kill(getppid(), SIGINT);
      }    
    }
    sleep(number); // sleep for number seconds, value passed as a parameter.
  }
}



int main(void)
{
  int t;
  pthread_t tid[13]; // an array to keep track of the threads

  // To create a detached thread.
  pthread_attr_t attr; // thread attribute

  // To call to pthread_attr_get...
  int rc, val;
  struct sched_param sp;
  size_t v;
  void *stkaddr;


  signal(SIGINT, siginthandler);

  printf ("[parent] pid = %d\n", getpid());

  gettimeofday(&begin, NULL);

  for (t=1; t<3; t++)
    {
    pthread_create(&tid[t],NULL,(void *)ThreadRoutine,(int *)t);
    printf ("Created thread %d with id=%d\n", t, (int)tid[t]);
    }

  sleep(30);

  return 0;
}

程序运行时的屏幕输出：

[parent] pid = 18994
Created thread 1 with id=1463871232
[thread 1] pthread_self = 1463871232, getpid = 18994, getppid = 25402
thread type 1 (1) running
Microseconds from starting time = 175
[thread 2] pthread_self = 1455478528, getpid = 18994, getppid = 25402
thread type 1 (2) running
Created thread 2 with id=1455478528
thread type 1 (1) running
Microseconds from starting time = 1000319
thread type 1 (2) running
thread type 1 (1) running
Microseconds from starting time = 2000536
thread type 1 (1) running
Microseconds from starting time = 3000722
thread type 1 (2) running
thread type 1 (1) running
Microseconds from starting time = 4000819
thread type 1 (1) running
Microseconds from starting time = 5000997
thread type 1 (2) running
thread type 1 (1) running
Microseconds from starting time = 6001088
thread type 1 (1) running
Microseconds from starting time = 7001264
thread type 1 (2) running
thread type 1 (1) running
Microseconds from starting time = 8001383
thread type 1 (1) running
Microseconds from starting time = 9001556
thread type 1 (2) running
thread type 1 (1) running
Microseconds from starting time = 10001677
Killing parent process after 10 seconds from starting.
Segmentation fault (core dumped)

【问题讨论】：

在SEGV之前你得到了什么输出......？？
在原始问题的 ehd 中添加了整个输出。
如果对 thread_kill() 的调用被 exit() 替换，程序将在没有分段错误的情况下完成。这是一个好的解决方案吗？是否可以使用父进程的 PID 来杀死父进程？
Ubuntu 18.04 的 pthread_kill() 手册页有这个原型： int pthread_kill(pthread_t thread, int sig);... 注意第一个参数是“threadID”，而不是进程 ID您已通过 getppid() 指定。
谢谢，我改用 pthread_self()，程序运行正常。

标签： c linux multithreading segmentation-fault signals

【解决方案1】：

Ubuntu 18.04 的 pthread_kill() 的手册页有这个原型：int pthread_kill(pthread_t thread, int sig);... 注意第一个参数是“threadID”，而不是您通过 getppid() 指定的进程 ID。 – 托尼B

我改用pthread_self()，程序运行正常。 – jstechg

【讨论】：

【解决方案2】：

关于：

启动 10 秒后杀死父进程

线程不是子进程。所以线程函数中的代码试图杀死设置/运行程序的进程（可能是shell）

【讨论】：