Cannot get Samba core dumps

[Andrea Venturoli]

Hello.

I've recently installed net/samba410 in a 11.3/amd64 jail (like I've 
done several times before(.

Unlike all other cases, in this particular instance smbd is crashing 
often, but won't dump any core file.
In the logs I find:
> [2019/11/22 12:34:37.366207,  0] ../../source3/lib/dumpcore.c:310(dump_core)
>   unable to change to %N.core
>   refusing to dump core

So I tried "sysctl kern.corefile=/root/%N_%P.pid".
Now I see:
> [2019/11/29 12:54:14.946952,  0] ../../source3/lib/dumpcore.c:315(dump_core)
>   dumping core in /root

Still there's no core in jail's /root, nor base's /root!

I remember having examined Samba cores in the past...

What should I do to be able to get them again?

  bye & Thanks
	av.