[Samba] Signal 11 on domain join (Debian 10 Samba 4.9.5+dfsg-5+deb10u1)

[Andrew Bartlett]

On Wed, 2020-11-11 at 19:19 -0800, Aaron C. de Bruyn via samba wrote:
> I wanted to do a little playtesting with Samba as a domain
> controller.
> I spun up a Debian 10 box, installed Samba (package 4.9.5+dfsg-
> 5+deb10u1) ,
> and attempted to join it to the domain.  It crashed horribly. ;)
> 

> ===============================================================
> INTERNAL ERROR: Signal 11 in pid 11893 (4.9.5-Debian)
> Please read the Trouble-Shooting section of the Samba HOWTO
> ===============================================================
> smb_panic_default: PANIC (pid 11893): internal error
> BACKTRACE: 53 stack frames:
>  #0 /lib/x86_64-linux-gnu/libsamba-util.so.0(log_stack_trace+0x32)
> [0x7fe2e709a8d2]
>  #1 /lib/x86_64-linux-gnu/libsamba-util.so.0(smb_panic+0x52)
> [0x7fe2e709aa02]
>  #2 /lib/x86_64-linux-gnu/libsamba-util.so.0(+0x24c16)
> [0x7fe2e709ac16]
>  #3 /lib/x86_64-linux-gnu/libpthread.so.0(+0x12730) [0x7fe2e7eec730]
>  #4 /lib/x86_64-linux-gnu/libldb.so.1(+0xbc9f) [0x7fe2e74cec9f]
>  #5
> /lib/x86_64-linux-
> gnu/libldb.so.1(ldb_ldif_write_redacted_trace_string+0x4f)
> [0x7fe2e74d027f]
>  #6
> /lib/x86_64-linux-
> gnu/libldb.so.1(ldb_ldif_message_redacted_string+0x24)
> [0x7fe2e74d0394]


> After doing a bunch of reading through the list, and the args to
> samba-tool, I tried adding the flag --domain-critical-only and it
> joined
> without a problem.

OK.  

> I'm curious if Samba will have problems replicating 'non-critical'
> domain
> data now that the join is finished...although I'm not entirely sure
> what
> the difference is between critical and non-critical data in LDAP.

It should just blat the whole domain over the top but be in better
position to do so because the skeleton the of domain is already in
place.

> Regardless, I figured someone might want me to do a bit more digging
> to
> find out what's causing the crash.

If you could re-run it under valgrind that might help.

PYTHONMALLOC=malloc valgrind python3 /path/to/samba-tool ...

Ideally do it with a modern Samba however, so we don't just chase down
bugs we have already fixed.

Thanks,

Andrew Bartlett

-- 
Andrew Bartlett
https://samba.org/~abartlet/
Authentication Developer, Samba Team         https://samba.org
Samba Development and Support, Catalyst IT - Expert Open Source
Solutions
https://catalyst.net.nz/services/samba