[Bug c++/30384] New: gdbserver get an error when father process exit

[Bug c++/30384] New: gdbserver get an error when father process exit

[hewei4321017 at 163 dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30384

            Bug ID: 30384
           Summary: gdbserver get an error when father process exit
           Product: gdb
           Version: 13.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
          Assignee: unassigned at sourceware dot org
          Reporter: hewei4321017 at 163 dot com
  Target Milestone: ---

Overview:
  when debugging multi-process with gdb and gdbserver on ubuntu 22.04,
gdbserver get 
an error "Cannot get thread handle for LWP 556726: generic error" when parent
exit

Steps to Reproduce:
1、compile excutable
g++ main.cpp -g -o test

2、run gdbserver with command 
hewei@hewei-VirtualBox:~/project/gdb-13.1$ ./gdbserver/gdbserver  0.0.0.0:5012
/home/hewei/project/testipc/src/main/test
Process /home/hewei/project/testipc/src/main/test created; pid = 557078
Listening on port 5012

3、run gdb and input the following command
set mi-async on
set detach-on-fork off
set follow-fork-mode parent
set schedule-multiple on
target remote 10.27.8.145:5012
continue

4、when father process exit，gdbserver will get an error. 
Child exited with status 0
gdbserver: Cannot get thread handle for LWP 557093: generic error

5、After that，it won't be able to debug the child process any more. When I try
to switch to the child and press "ctrl + c" to interrupt the child in gdb, it
will output the following msg:

Reading
/usr/local/lib/debug/.build-id/02/17e95cdd5172617b053d3772efce4317a55898.debug
from remote target...
[Inferior 1 (process 557078) exited normally]
(gdb) info inferior
  Num  Description       Connection                  Executable
* 1    <null>            1 (remote 10.27.8.145:5012)
target:/home/hewei/project/testipc/src/main/test
  2    process 557093    1 (remote 10.27.8.145:5012)
target:/home/hewei/project/testipc/src/main/test
(gdb) inferior 2
[Switching to inferior 2 [process 557093]
(target:/home/hewei/project/testipc/src/main/test)]
[Switching to thread 2.1 (Thread 557093.557093)]
^C
^CThe target is not responding to GDB commands.
Stop debugging it? (y or n)

Actual Results:
  unable to continue debugging child process

Actual Results:
  After parent exit, I can continue to debug the child.

Additional Builds and Platforms
   gdb and gdbserver are built on ubuntu 22.04 with gcc 7.55

hewei@hewei-VirtualBox:~/project/testipc/src/main$ gcc --version
gcc (Ubuntu 7.5.0-6ubuntu2) 7.5.0
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

build command:
./configure --enable-targets=aarch64-linux-gnu,x86_64-linux-gnu 
CFLAGS="-lpthread -g" CXXFLAGS="-lpthread -g" LIBS="-lpthread -g" && make

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[Bug c++/30384] gdbserver get an error when father process exit

[hewei4321017 at 163 dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30384

--- Comment #1 from 贺伟 <hewei4321017 at 163 dot com> ---
sorry, 
>>>After parent exit, I can continue to debug the child.
This is the Expected Results, not Actual Results

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[Bug c++/30384] gdbserver get an error when father process exit

[hewei4321017 at 163 dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30384

--- Comment #2 from 贺伟 <hewei4321017 at 163 dot com> ---
Created attachment 14845
  --> https://sourceware.org/bugzilla/attachment.cgi?id=14845&action=edit
test code

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[Bug c++/30384] gdbserver get an error when father process exit

[hewei4321017 at 163 dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30384

--- Comment #3 from 贺伟 <hewei4321017 at 163 dot com> ---
Comment on attachment 14845
  --> https://sourceware.org/bugzilla/attachment.cgi?id=14845
test code

#include <stdlib.h>
#include <stdio.h>
#include <iostream>
#include <ostream>
#include <unistd.h>
#include <string.h>
#include<algorithm>
#include <assert.h>
#include <sys/types.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <pthread.h>
#include <map>
#include <vector>
#include <sys/ptrace.h>
#include <sys/prctl.h>
#include <sys/user.h>
#include <sys/syscall.h>


using namespace std;
int main(int args, char* argv[], char* envp[])
{

    int g = 1;
    pid_t pid = fork();
    if (pid < 0) {
        return -1;
    } else if (pid == 0) {
        int i = 0;
        while (1) {
            int a = 3;
            i++;
            cout << "child:" << getpid() << endl;
            sleep(2);
        }

    } else if (pid > 0) {
        // cout << "father pid:"<<  getpid() << endl;

        int i = 0;
        while (i<5) {
            cout << "father:" << getpid() << endl;
            i++;
            sleep(2);
        }
        exit(0);

    }

    return 0;

}

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[Bug c++/30384] gdbserver get an error when father process exit

[hewei4321017 at 163 dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30384

贺伟 <hewei4321017 at 163 dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #14845|0                           |1
        is obsolete|                            |

--- Comment #4 from 贺伟 <hewei4321017 at 163 dot com> ---
Created attachment 14846
  --> https://sourceware.org/bugzilla/attachment.cgi?id=14846&action=edit
test code

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[Bug c++/30384] gdbserver get an error when father process exit

[hewei4321017 at 163 dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30384

贺伟 <hewei4321017 at 163 dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #14846|0                           |1
        is obsolete|                            |

--- Comment #5 from 贺伟 <hewei4321017 at 163 dot com> ---
Created attachment 14847
  --> https://sourceware.org/bugzilla/attachment.cgi?id=14847&action=edit
test code

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[Bug server/30384] gdbserver get an error when father process exit

[tromey at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30384

Tom Tromey <tromey at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c++                         |server
                 CC|                            |tromey at sourceware dot org

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