Using source3 RPC servers as daemons causes deadlock with winbindd!

[Andreas Schneider]

On Wednesday 30 April 2014 11:55:40 Andrew Bartlett wrote:
> The attached patches finally make the source3 winbindd code connect to
> the LSA and SAMR servers over ncalrpc rather than directly linking the
> shared library.
> 
> The problem is, in make test s3dc is set to use:
> 
> 
>         rpc_server:epmapper = external
>         rpc_server:spoolss = external
>         rpc_server:lsarpc = external
>         rpc_server:samr = external
>         rpc_server:netlogon = external
>         rpc_server:register_embedded_np = yes
> 
>         rpc_daemon:epmd = fork
>         rpc_daemon:spoolssd = fork
>         rpc_daemon:lsasd = fork
> 
> The issue is, when we connect to the RPC server, we lock up due to a
> recursive call to winbindd (otherwise prevented because of the
> winbind_off() call).
> 
> It can be reproduced with:
> make test TESTS=samba3.blackbox.smbclient_auth.plain
> 
> GDB backtraces for smbd and winbindd are attached.
> 
> It appears to be locking up looking via LSA lookupnames and an NSS call
> for unix group\nogroup
> 
> Do you think it is reasonable to expect the source3 LSA and SAMR servers
> to be able to service winbindd when not loaded as a shared library, or
> should we instead put an exception in for this (only use the pipes when
> in AD DC mode).
> 
> Your thoughts and comments would be most valued.  As mentioned above,
> the patch used the to reproduce this is also attached.

I'll leave today and will back on monday. Then I can look into this.

Maybe Simo has time ...



	-- andreas

-- 
Andreas Schneider                   GPG-ID: CC014E3D
Samba Team                             asn at samba.org
www.samba.org