Samba dump (useless) core

[Konstantin Belousov]

On Wed, May 08, 2019 at 12:03:34PM +0200, Andrea Venturoli wrote:
> Hello.
> 
> I've got a few servers where I run Samba 4.8 in a jail as an AD DC.
> 
> Lately, on a couple of them, it started dumping core: on one server, 
> apparently everything works fine after that; on another one I have 
> intermittent DNS issues, but I'm not sure they are related to this core.
> 
> I tried examining the core, but this is what I get:
> 
> > # gdb /usr/local/sbin/samba samba.core
> > GNU gdb 6.1.1 [FreeBSD]
> > Copyright 2004 Free Software Foundation, Inc.
> > GDB is free software, covered by the GNU General Public License, and you are
> > welcome to change it and/or distribute copies of it under certain conditions.
> > Type "show copying" to see the conditions.
> > There is absolutely no warranty for GDB.  Type "show warranty" for details.
> > This GDB was configured as "amd64-marcel-freebsd"...
> > Core was generated by `samba: conn[rpc] c[ipv4:192.168.xxx.4:31803] s[ipv4:192.168.134.3:49153] server_'.
> > Program terminated with signal 6, Aborted.
> > #0  0x0000000803e0d98a in ?? ()
> > (gdb) info thr
> > * 1 process 101460  0x0000000803e0d98a in ?? ()
> > (gdb) bt
> > #0  0x0000000803e0d98a in ?? ()
> > #1  0x0000000803e0d940 in ?? ()
> > #2  0xffffffffffffffdf in ?? ()
> > #3  0xffffffffffffffff in ?? ()
> > #4  0x0000000000000000 in ?? ()
> > (gdb) 
> 
> The only relevant line, unfortunately is "Core was generated by...", but 
> it doesn't help much.
> 
> Samba is compiled (via Pudriere) with DEBUG, so I thought the above 
> would be more useful.
> 
> Any hint?
Signal 6 is SIGABRT, which means most likely that some assert was triggered.
You should look into your logs.  Also it is possible that DEBUG turns on
asserts.