Just upgraded from 12.04 to 14.04 and now Winbind is panicking about 10 times an hour, always in the same place.
Backtrace:
0x00007f0e7262a98c in __libc_waitpid (pid=29930, stat_loc=stat_loc@entry=0x7fff82f48d10, options=options@entry=0) at ../sysdeps/unix/sysv/linux/waitpid.c:31
#0 0x00007f0e7262a98c in __libc_waitpid (pid=29930, stat_loc=stat_loc@entry=0x7fff82f48d10, options=options@entry=0) at ../sysdeps/unix/sysv/linux/waitpid.c:31
#1 0x00007f0e725af592 in do_system (line=line@entry=0x7f0e7b4221d0 "/usr/share/samba/panic-action 29929") at ../sysdeps/posix/system.c:148
#2 0x00007f0e725af8fa in __libc_system (line=line@entry=0x7f0e7b4221d0 "/usr/share/samba/panic-action 29929") at ../sysdeps/posix/system.c:184
#3 0x00007f0e78fcd235 in system (line=line@entry=0x7f0e7b4221d0 "/usr/share/samba/panic-action 29929") at pt-system.c:28
#4 0x00007f0e748c6061 in smb_panic_s3 (why=<optimized out>) at ../source3/lib/util.c:798
#5 0x00007f0e78b9fc6f in smb_panic (why=why@entry=0x7f0e78babb3b "internal error") at ../lib/util/fault.c:159
#6 0x00007f0e78b9fe86 in fault_report (sig=<optimized out>) at ../lib/util/fault.c:77
#7 sig_fault (sig=<optimized out>) at ../lib/util/fault.c:88
#8 <signal handler called>
#9 0x00007f0e72683ca4 in inet_pton4 (dst=0x7fff82f49490 "\330\224\364\202\377\177", src=0x1 <error: Cannot access memory at address 0x1>) at inet_pton.c:93
#10 __GI_inet_pton (af=af@entry=2, src=src@entry=0x0, dst=dst@entry=0x7fff82f49490) at inet_pton.c:59
#11 0x00007f0e78b9c2c4 in is_ipaddress_v4 (str=str@entry=0x0) at ../lib/util/util_net.c:316
#12 0x00007f0e78b9c569 in is_ipaddress (str=str@entry=0x0) at ../lib/util/util_net.c:366
#13 0x00007f0e75449863 in internal_resolve_name (name=name@entry=0x0, name_type=name_type@entry=28, sitename=sitename@entry=0x7f0e7b3fc990 "UK-SEE", return_iplist=return_iplist@entry=0x7fff82f49678, return_count=return_count@entry=0x7fff82f49664, resolve_order=resolve_order@entry=0x7f0e756598b0 <ads_order>) at ../source3/libsmb/namequery.c:2600
#14 0x00007f0e7544a9c9 in get_dc_list (domain=domain@entry=0x0, sitename=sitename@entry=0x7f0e7b3fc990 "DOMAIN", ip_list=ip_list@entry=0x7fff82f49830, count=count@entry=0x7fff82f4982c, lookup_type=lookup_type@entry=DC_ADS_ONLY, ordered=ordered@entry=0x7fff82f4979f) at ../source3/libsmb/namequery.c:3114
#15 0x00007f0e7544b90f in get_sorted_dc_list (domain=0x0, sitename=sitename@entry=0x7f0e7b3fc990 "DOMAIN", ip_list=ip_list@entry=0x7fff82f49830, count=count@entry=0x7fff82f4982c, ads_only=ads_only@entry=true) at ../source3/libsmb/namequery.c:3295
#16 0x00007f0e794442fd in get_dcs (mem_ctx=mem_ctx@entry=0x7f0e7b42e280, domain=domain@entry=0x7f0e7b3f5990, dcs=dcs@entry=0x7fff82f49ae8, num_dcs=num_dcs@entry=0x7fff82f49ad8) at ../source3/winbindd/winbindd_cm.c:1348
#17 0x00007f0e7944581e in find_new_dc (fd=0x7fff82f49ad4, pss=0x7f0e7b3f5a40, dcname=0x7fff82f49ae0, domain=0x7f0e7b3f5990, mem_ctx=0x7f0e7b42e280) at ../source3/winbindd/winbindd_cm.c:1455
#18 cm_open_connection (new_conn=0x7f0e7b3f5ad0, domain=0x7f0e7b3f5990) at ../source3/winbindd/winbindd_cm.c:1692
#19 init_dc_connection_network (domain=0x7f0e7b3f5990) at ../source3/winbindd/winbindd_cm.c:1892
#20 0x00007f0e79446645 in init_dc_connection (domain=domain@entry=0x7f0e7b3f5990) at ../source3/winbindd/winbindd_cm.c:1912
#21 0x00007f0e79446659 in init_dc_connection_rpc (domain=domain@entry=0x7f0e7b3f5990) at ../source3/winbindd/winbindd_cm.c:1919
#22 0x00007f0e794471df in cm_connect_lsa (domain=domain@entry=0x7f0e7b3f5990, mem_ctx=mem_ctx@entry=0x7f0e7b42ef00, cli=cli@entry=0x7fff82f49d08, lsa_policy=lsa_policy@entry=0x7fff82f49d20) at ../source3/winbindd/winbindd_cm.c:2580
#23 0x00007f0e79447761 in cm_connect_lsat (domain=domain@entry=0x7f0e7b3f5990, mem_ctx=mem_ctx@entry=0x7f0e7b42ef00, cli=cli@entry=0x7fff82f49d08, lsa_policy=lsa_policy@entry=0x7fff82f49d20) at ../source3/winbindd/winbindd_cm.c:2729
#24 0x00007f0e7944c43e in rpc_lookup_sids (mem_ctx=0x7f0e7b42ef00, domain=domain@entry=0x7f0e7b3f5990, sids=0x7f0e7b42c8a0, pdomains=pdomains@entry=0x7f0e7b42d358, pnames=pnames@entry=0x7f0e7b42d360) at ../source3/winbindd/winbindd_rpc.c:1135
#25 0x00007f0e7945675b in _wbint_LookupSids (p=p@entry=0x7fff82f49df0, r=r@entry=0x7f0e7b42d350) at ../source3/winbindd/winbindd_dual_srv.c:89
#26 0x00007f0e7947cda0 in api_wbint_LookupSids (p=0x7fff82f49df0) at default/source3/librpc/gen_ndr/srv_wbint.c:230
#27 0x00007f0e79456571 in winbindd_dual_ndrcmd (domain=<optimized out>, state=0x7fff82f4a068) at ../source3/winbindd/winbindd_dual_ndr.c:322
#28 0x00007f0e7945337c in child_process_request (child=<optimized out>, child=<optimized out>, state=0x7fff82f4a068) at ../source3/winbindd/winbindd_dual.c:459
#29 child_handler (ev=<optimized out>, fde=<optimized out>, flags=<optimized out>, private_data=0x7fff82f4a060) at ../source3/winbindd/winbindd_dual.c:1343
#30 0x00007f0e7293767b in ?? () from /usr/lib/x86_64-linux-gnu/libtevent.so.0
#31 0x00007f0e72935b27 in ?? () from /usr/lib/x86_64-linux-gnu/libtevent.so.0
#32 0x00007f0e729325ed in _tevent_loop_once () from /usr/lib/x86_64-linux-gnu/libtevent.so.0
#33 0x00007f0e79455702 in fork_domain_child (child=0x7f0e7b3f5bd0) at ../source3/winbindd/winbindd_dual.c:1558
#34 0x00007f0e79455db5 in wb_child_request_trigger (req=0x7f0e7b430090, private_data=<optimized out>) at ../source3/winbindd/winbindd_dual.c:146
#35 0x00007f0e72932e14 in tevent_common_loop_immediate () from /usr/lib/x86_64-linux-gnu/libtevent.so.0
#36 0x00007f0e72937437 in ?? () from /usr/lib/x86_64-linux-gnu/libtevent.so.0
#37 0x00007f0e72935b27 in ?? () from /usr/lib/x86_64-linux-gnu/libtevent.so.0
#38 0x00007f0e729325ed in _tevent_loop_once () from /usr/lib/x86_64-linux-gnu/libtevent.so.0
#39 0x00007f0e79424e42 in main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at ../source3/winbindd/winbindd.c:1588
Winbind Version: 2:4.1.6+