core_uses_pid==0 still produces core.PID

[Philippe De Muyter <phdm@macqel.be>]

Hello everybody

I have a process that produces core files of the form "core.PID".

I read in the docs the core file name can be controlled by
/proc/sys/kernel/core_pattern and /proc/sys/kernel/core_uses_pid.

On my machine, they have the value "core" and 0, so I would expect the
core files named "core", not "core.PID".

If I start "sleep 100" and kill it with CTRL-C, I indeed get a file
named "core", but with my interesting process the files are always named
"core.PID".

Looking at the fs/exec.c sources, I see that core_uses_pid is superseded
by
	atomic_read(&current->mm->mm_users) != 1

Why is that needed there ? When my process crashes or is killed, I always
get only one core file, not many core files, although my process is
multi-threaded.

Is that a rest of a previous thread implementation that could now be removed ?

Best regards

Philippe