(gdb) bt
#0  0x00007f04d001d148 in pthread_join () from /lib/x86_64-linux-gnu/libpthread.so.0
#1  0x000000000043ae59 in slapd_daemon () at daemon.c:2929
#2  0x0000000000422c00 in main (argc=5, argv=<optimized out>) at main.c:1012
(gdb) next
Single stepping until exit from function pthread_join,
which has no line number information.

Program received signal SIGABRT, Aborted.
[Switching to Thread 0x7f04c77fe700 (LWP 30546)]
0x00007f04cfc8d445 in raise () from /lib/x86_64-linux-gnu/libc.so.6
(gdb) bt
#0  0x00007f04cfc8d445 in raise () from /lib/x86_64-linux-gnu/libc.so.6
#1  0x00007f04cfc90bab in abort () from /lib/x86_64-linux-gnu/libc.so.6
#2  0x00007f04cfc8610e in ?? () from /lib/x86_64-linux-gnu/libc.so.6
#3  0x00007f04cfc861b2 in __assert_fail () from /lib/x86_64-linux-gnu/libc.so.6
#4  0x00000000005209c6 in ldap_chain_uri_cmp (c1=<optimized out>, c2=<optimized out>) at chain.c:227
#5  0x00000000005992f1 in avl_find (root=0x1235930, data=0x7f04c77fb880, 
    fcmp=0x520940 <ldap_chain_uri_cmp>) at avl.c:545
#6  0x0000000000522b80 in ldap_chain_op (op=0x7f04c010fb60, rs=0x7f04c77fdae0, 
    op_f=0x4c8fb0 <ldap_back_modify>, ref=0x7f04c011bcb0, depth=0) at chain.c:559
#7  0x0000000000523999 in ldap_chain_response (op=0x7f04c010fb60, rs=0x7f04c77fdae0) at chain.c:1090
#8  0x00000000004a5628 in over_back_response (op=0x7f04c010fb60, rs=0x7f04c77fdae0) at backover.c:237
#9  0x000000000044c407 in slap_response_play (op=0x7f04c010fb60, rs=0x7f04c77fdae0) at result.c:508
#10 0x000000000044c93a in send_ldap_response (op=0x7f04c010fb60, rs=0x7f04c77fdae0) at result.c:583
#11 0x000000000044d36b in slap_send_ldap_result (op=0x7f04c010fb60, rs=0x7f04c77fdae0) at result.c:861
#12 0x0000000000453b95 in fe_op_modify (op=0x7f04c010fb60, rs=0x7f04c77fdae0) at modify.c:318
#13 0x00000000004a6156 in overlay_op_walk (op=0x7f04c010fb60, rs=0x7f04c77fdae0, which=op_modify, 
    oi=0x122eef0, on=0x0) at backover.c:677
#14 0x00000000004a62c1 in over_op_func (op=0x7f04c010fb60, rs=<optimized out>, which=<optimized out>)
    at backover.c:730
#15 0x0000000000455873 in do_modify (op=0x7f04c010fb60, rs=0x7f04c77fdae0) at modify.c:177
#16 0x000000000043d709 in connection_operation (ctx=0x7f04c77fdba0, arg_v=0x7f04c010fb60)
    at connection.c:1155
#17 0x000000000059d5e8 in ldap_int_thread_pool_wrapper (xpool=0x1175b80) at tpool.c:688
#18 0x00007f04d001be9a in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
#19 0x00007f04cfd494bd in clone () from /lib/x86_64-linux-gnu/libc.so.6
#20 0x0000000000000000 in ?? ()