[Samba] 'samba-tool dbcheck' reports only a "Bus error"

Tue Oct 27 10:40:14 UTC 2015

Andrew, thank you for your help! Could a "Bus error" be related to a 
hardware problem? Never seen it before.

Anyways, here is the output of my debugging session (I hope I did 
everything correctly):

[root at server bin]# gdb --args python /usr/local/samba/bin/samba-tool dbcheck
GNU gdb (GDB) Red Hat Enterprise Linux (7.2-75.el6)
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later 
<http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i686-redhat-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/bin/python...(no debugging symbols found)...done.
Missing separate debuginfos, use: debuginfo-install python-2.6.6-52.el6.i686
(gdb) run
Starting program: /usr/bin/python /usr/local/samba/bin/samba-tool dbcheck
[Thread debugging using libthread_db enabled]
Detaching after fork from child process 26458.
Detaching after fork from child process 26460.

Program received signal SIGBUS, Bus error.
0x00378296 in __memcpy_ia32 () from /lib/libc.so.6
(gdb) backtrace
#0  0x00378296 in __memcpy_ia32 () from /lib/libc.so.6
#1  0x0051da2b in py_ldb_schema_format_value () from 
/usr/local/samba/lib/python2.6/site-packages/ldb.so
#2  0x006efeca in tdb_rec_read () from 
/usr/local/samba/lib/private/libtdb.so.1
#3  0x006eb02d in tdb_next_lock () from 
/usr/local/samba/lib/private/libtdb.so.1
#4  0x006eb3dc in tdb_traverse_internal () from 
/usr/local/samba/lib/private/libtdb.so.1
#5  0x006eb499 in tdb_traverse_read () from 
/usr/local/samba/lib/private/libtdb.so.1
#6  0x0270b562 in ltdb_search_full () from /usr/local/samba/lib/ldb/tdb.so
#7  0x0270b8b4 in ltdb_search () from /usr/local/samba/lib/ldb/tdb.so
#8  0x02709f1e in ltdb_callback () from /usr/local/samba/lib/ldb/tdb.so
#9  0x005072a3 in tevent_common_loop_timer_delay () from 
/usr/local/samba/lib/private/libtevent.so.0
#10 0x005095dd in epoll_event_loop_once () from 
/usr/local/samba/lib/private/libtevent.so.0
#11 0x0050664a in std_event_loop_once () from 
/usr/local/samba/lib/private/libtevent.so.0
#12 0x00501533 in _tevent_loop_once () from 
/usr/local/samba/lib/private/libtevent.so.0
#13 0x0054d95a in ldb_wait () from /usr/local/samba/lib/private/libldb.so.1
#14 0x0051dd87 in py_ldb_search () from 
/usr/local/samba/lib/python2.6/site-packages/ldb.so
#15 0x00193b28 in PyCFunction_Call () from /usr/lib/libpython2.6.so.1.0
#16 0x001eddbb in PyEval_EvalFrameEx () from /usr/lib/libpython2.6.so.1.0
#17 0x001ee98a in PyEval_EvalCodeEx () from /usr/lib/libpython2.6.so.1.0
#18 0x001eca83 in PyEval_EvalFrameEx () from /usr/lib/libpython2.6.so.1.0
#19 0x001ee98a in PyEval_EvalCodeEx () from /usr/lib/libpython2.6.so.1.0
#20 0x00181f27 in ?? () from /usr/lib/libpython2.6.so.1.0
#21 0x001585cd in PyObject_Call () from /usr/lib/libpython2.6.so.1.0
#22 0x001eba5b in PyEval_EvalFrameEx () from /usr/lib/libpython2.6.so.1.0
#23 0x001ee98a in PyEval_EvalCodeEx () from /usr/lib/libpython2.6.so.1.0
#24 0x00181e28 in ?? () from /usr/lib/libpython2.6.so.1.0
#25 0x001585cd in PyObject_Call () from /usr/lib/libpython2.6.so.1.0
#26 0x001eba5b in PyEval_EvalFrameEx () from /usr/lib/libpython2.6.so.1.0
#27 0x001ee98a in PyEval_EvalCodeEx () from /usr/lib/libpython2.6.so.1.0
#28 0x00181e28 in ?? () from /usr/lib/libpython2.6.so.1.0
#29 0x001585cd in PyObject_Call () from /usr/lib/libpython2.6.so.1.0
#30 0x001eba5b in PyEval_EvalFrameEx () from /usr/lib/libpython2.6.so.1.0
#31 0x001ee98a in PyEval_EvalCodeEx () from /usr/lib/libpython2.6.so.1.0
#32 0x001eeaa4 in PyEval_EvalCode () from /usr/lib/libpython2.6.so.1.0
#33 0x00208e6c in ?? () from /usr/lib/libpython2.6.so.1.0
#34 0x00208f33 in PyRun_FileExFlags () from /usr/lib/libpython2.6.so.1.0
#35 0x0020a5b1 in PyRun_SimpleFileExFlags () from 
/usr/lib/libpython2.6.so.1.0
#36 0x0020ae62 in PyRun_AnyFileExFlags () from /usr/lib/libpython2.6.so.1.0
#37 0x0021776b in Py_Main () from /usr/lib/libpython2.6.so.1.0
#38 0x080485c8 in main ()

Am 27.10.2015 um 06:40 schrieb Andrew Bartlett:
> On Sun, 2015-10-25 at 16:14 +0100, Ole Traupe wrote:
>> For a few days now my primary DC has some issues. I can create users
>> without a problem. But when I try to alter the group membership of
>> users, one of my samba processes crashes (the one listening to the
>> LDAP
>> related ports: 389, 636, 3268, 3269).
>>
>> Also, when I start my backup DC, a few seconds later another process
>> crashes on the primary DC (the RPC related listening to 135 and
>> 1024).
>>
>> I haven't made any updates to OS or Samba (still 4.2.2), but I have
>> adjusted some UIDs and GIDs recently.
>>
>> Despite "log level = 3", the "log.samba" gives only this,
>>
>> [2015/10/22 19:05:46.500567,  0] ../lib/util/fault.c:78(fault_report)
>>     ===============================================================
>> [2015/10/22 19:05:46.515490,  0] ../lib/util/fault.c:79(fault_report)
>>     INTERNAL ERROR: Signal 7 in pid 3794 (4.2.2)
>>     Please read the Trouble-Shooting section of the Samba HOWTO
>> [2015/10/22 19:05:46.515633,  0] ../lib/util/fault.c:81(fault_report)
>>     ===============================================================
>> [2015/10/22 19:05:46.515732,  0]
>> ../lib/util/fault.c:151(smb_panic_default)
>>     PANIC: internal error
>>
>> while the trouble shooting page directs me to the log files. ;)
>>
>> When I try a 'samba-tool dbcheck' on the PDC, I get the message "Bus
>> error". Nothing more. When I do it on the BDC, the check runs through
>> without errors. The sam.ldb on the BDC is in an earlier state because
>> replication isn't working any more.
>>
>> What does "Bus error" mean? Have I messed up my data base? Or is it
>> something else?
> What I suggest is running samba-tool under gdb --args, and then getting
> a backtrace.  That will give a clue to where in the C code we are
> faulting (if that is the case), and so what the likely issue is.  We
> can then proceed to fixing both.
>
> gdb --args python /usr/local/bin/samba-tool
>
> Andrew Bartlett
>