Subject: bug#54183: 28.0.91; Emacs crashes on bookmark-jump

From: Gustavo Barros <[email-masked]>
Date: Mon, 28 Feb 2022 11:30:51 -0300

On Mon, 28 Feb 2022 at 15:17, Eli Zaretskii <[email-masked]> wrote:

> This means your system disables the system call that allows GDB to
> attach to a running process.  Can you change the setting the error
> message mentions above, or ask your sysadmins to change it for you, or
> do something else to grant you the privilege of attaching a debugger
> to a process?  If you can do that, please try this method again after
> enabling that privilege.

It's a personal computer, so I'm the "sysadmin".  It was a setting done 
by the distro, and I changed it.  Then I tried the following.

Started `./emacsclient -c -a=""' and then `M-x gdb RET gdb -i=mi -p 
<emacs pid> RET'.  Where the PID was the same and only instance of Emacs 
I had opened.  This resulted in GDB getting stuck at "initializing...". 
I presume "attaching to itself" is not the thing.

So I started two Emacs instances, one `./emacsclient -c -a=""' from 
`lib-src/', and another standalone instance.  So I starded GDB from the 
standalone instance using the PID from the daemon with `M-x gdb RET gdb 
-i=mi -p <emacs daemon pid> RET'.  This gets me almost there I think, 
but not quite.  It appears to attach successfully:

#+begin_example
Attaching to process 10785
[New LWP 10786]
[New LWP 10787]
[New LWP 10788]
[Thread debugging using libthread_db enabled]
Using host libthread_db library 
"/lib/x86_64-linux-gnu/libthread_db.so.1".
0x00007fa139664246 in __pselect (nfds=21, readfds=0x7fff480be100, 
writefds=0x7fff480be180, exceptfds=0x0, timeout=<optimized out>, 
sigmask=<optimized out>) at ../sysdeps/unix/sysv/linux/pselect.c:48
48	../sysdeps/unix/sysv/linux/pselect.c: No such file or directory.
#+end_example

However, I also get a message that "Target doesn’t support non-stop 
mode.  Turning it off."  And indeed, the other instance to which I 
attached GDB becomes completely unresponsive until I quit GDB, so I 
cannot trigger the problem, since I cannot interact with it.