[Bug gdb/9585] GNU/Linux x86, gdb freezes after fork wit detach-on-fork off and follow-fork-mode child

[Bug gdb/9585] GNU/Linux x86, gdb freezes after fork wit detach-on-fork off and follow-fork-mode child

[palves at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=9585

Pedro Alves <palves at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|                            |FIXED

--- Comment #12 from Pedro Alves <palves at redhat dot com> 2012-10-24 15:52:26 UTC ---
As above.

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[Bug gdb/9585] GNU/Linux x86, gdb freezes after fork wit detach-on-fork off and follow-fork-mode child

[palves at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=9585

Pedro Alves <palves at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |palves at redhat dot com

--- Comment #11 from Pedro Alves <palves at redhat dot com> 2012-10-24 15:52:10 UTC ---
> Pedro Alves 2010-04-06 10:33:35 UTC
>
> Can someone confirm this still happens with the latest release?  Seeing
> "set debug infrun 1" and "set debug lin-lwp 1" output would also be
> interesting.

No feedback on the original reported freeze in a couple years, and given this
was reported against 6.7, last we heard was in 2009, and we've had numerous
fixes to the fork support since, I'm closing this.

Thanks.

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[Bug gdb/9585] GNU/Linux x86, gdb freezes after fork wit detach-on-fork off and follow-fork-mode child

[pedro at codesourcery dot com]

------- Additional Comments From pedro at codesourcery dot com  2010-04-08 15:19 -------
These issues don't seem to have anything to do with gdb freezing, and we're
going quite offtopic by now.  Please open a new bug report.  While doing so,
please paste the relevant bit of the GDB session in the bug report body, and
describe what you think is wrong, so one doesn't have to open an attachment
and guess to quickly analyse the issue.  Thanks.


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[Bug gdb/9585] GNU/Linux x86, gdb freezes after fork wit detach-on-fork off and follow-fork-mode child

[flavio dot etrusco at gmail dot com]

------- Additional Comments From flavio dot etrusco at gmail dot com  2010-04-08 01:28 -------
Created an attachment (id=4710)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=4710&action=view)
gdb with sched-multiple on


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[Bug gdb/9585] GNU/Linux x86, gdb freezes after fork wit detach-on-fork off and follow-fork-mode child

[flavio dot etrusco at gmail dot com]

------- Additional Comments From flavio dot etrusco at gmail dot com  2010-04-08 01:26 -------
Forgot to attach "show version":

(gdb) show version
GNU gdb (GDB) 7.1-ubuntu
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i486-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
(gdb) 


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[Bug gdb/9585] GNU/Linux x86, gdb freezes after fork wit detach-on-fork off and follow-fork-mode child

[flavio dot etrusco at gmail dot com]

------- Additional Comments From flavio dot etrusco at gmail dot com  2010-04-08 01:25 -------
Thanks for the tip on "set schedule-multiple on", I've been looking for a
setting like this for quite some time in the documentation(s). 
But I anyway, trying gdb behavior seems erratic, not even running the child process.
Also, unfortunately the option didn't fix the problem for me.


>  Did you have "catch fork"/"catch vfork" set?
No.


> If the inferior exited, then it will have no process id, hence <null>.
Sure.

>> gdb says they have no threads.
> If the program isn't running anymore, it can't have any threads.
I meant the other inferiors, 1 and 2, not the exited inferior 3.


> I think most of your problems will go away with "set schedule-multiple on".
I'll attach the session (should have done it before...). 
Thanks.

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[Bug gdb/9585] GNU/Linux x86, gdb freezes after fork wit detach-on-fork off and follow-fork-mode child

[pedro at codesourcery dot com]

------- Additional Comments From pedro at codesourcery dot com  2010-04-07 23:33 -------
> My problem appears to be that a forked (notice that I don't really not what
syscall it uses) process doesn't freeze execution. 

Why would it?  Did you have "catch fork"/"catch vfork" set?

> If I Ctrl+C I can change
> inferiors and invoke 'continue'. Then this process forks another process,
again I Ctrl+C and change the inferior,

Did you mean to use "set schedule-multiple on" to have all inferiors
running simultaneously?

> then when I run it it seems to finish and gets
> listed as 'null' in the inferior list.

If the inferior exited, then it will have no process id, hence <null>.

> gdb says they have no threads.

If the program isn't running anymore, it can't have any threads.

I think most of your problems will go away with "set schedule-multiple on".

(gdb) help set schedule-multiple
Set mode for resuming threads of all processes.
When on, execution commands (such as 'continue' or 'next') resume all
threads of all processes.  When off (which is the default), execution
commands only resume the threads of the current process.  The set of
threads that are resumed is further refined by the scheduler-locking
mode (see help set scheduler-locking).


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[Bug gdb/9585] GNU/Linux x86, gdb freezes after fork wit detach-on-fork off and follow-fork-mode child

[flavio dot etrusco at gmail dot com]

------- Additional Comments From flavio dot etrusco at gmail dot com  2010-04-07 23:11 -------
Created an attachment (id=4709)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=4709&action=view)
gdb log with debugging info


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[Bug gdb/9585] GNU/Linux x86, gdb freezes after fork wit detach-on-fork off and follow-fork-mode child

[flavio dot etrusco at gmail dot com]

------- Additional Comments From flavio dot etrusco at gmail dot com  2010-04-07 23:03 -------
TBH I don't know whether this issue is the same I'm experiencing.
My problem appears to be that a forked (notice that I don't really not what
syscall it uses) process doesn't freeze execution. If I Ctrl+C I can change
inferiors and invoke 'continue'. Then this process forks another process, again
I Ctrl+C and change the inferior, then when I run it it seems to finish and gets
listed as 'null' in the inferior list. Then I can't continue the inferior, gdb
says they have no threads.
Funny thing is that I ran with the parameters you suggested. Before I ran it the
second time I enabled logging, than the execution did not freeze! I'll copy it
from the terminal and attach it.

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[Bug gdb/9585] GNU/Linux x86, gdb freezes after fork wit detach-on-fork off and follow-fork-mode child

[pedro at codesourcery dot com]

------- Additional Comments From pedro at codesourcery dot com  2010-04-06 10:33 -------
Can someone confirm this still happens with the latest release?  Seeing
"set debug infrun 1" and "set debug lin-lwp 1" output would also be
interesting.


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             Status|ASSIGNED                    |WAITING


http://sourceware.org/bugzilla/show_bug.cgi?id=9585

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[Bug gdb/9585] GNU/Linux x86, gdb freezes after fork wit detach-on-fork off and follow-fork-mode child

[flavio dot etrusco at gmail dot com]

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           What    |Removed                     |Added
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                   |                            |dot com


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[Bug gdb/9585] GNU/Linux x86, gdb freezes after fork wit detach-on-fork off and follow-fork-mode child

[matthijstijink at hotmail dot com]

------- Additional Comments From matthijstijink at hotmail dot com  2009-11-02 17:32 -------
My architecture is x86_64, by the way

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[Bug gdb/9585] GNU/Linux x86, gdb freezes after fork wit detach-on-fork off and follow-fork-mode child

[matthijstijink at hotmail dot com]

------- Additional Comments From matthijstijink at hotmail dot com  2009-11-02 17:30 -------
I confirm this behaviour. I didn't use wine, but with a lot of programs I tried
gdb just hangs.

I tried running a simple bash script but even that doesn't work. Sometimes
Ctrl-C can stop the process so you can quit gdb, but other times gdb hangs and
I have to kill it.

If you use 'set print inferior-events', you see that the new process is
started, but nothing happens.

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