(ITS#6200) slapd crashes under load w/ syncrepl

[frank.offermanns@caseris.de]

Hello,

i have the same problem with 2 Ubuntu 9.04 Systems with the current build 
from HEAD. I created 20000 entries at server1. Then i created another 
20000 entries at server1 while reading the old and new entries from 
server1 and server2. 
Here is the backtrace:

slapd: pthread_mutex_lock.c:289: __pthread_mutex_lock: Assertion `(-(e)) 
!= 3 || !robust' failed.

Program received signal SIGABRT, Aborted.
[Switching to Thread 0x923f9b90 (LWP 17860)]
0xb7fe0430 in __kernel_vsyscall ()
(gdb) bt
#0  0xb7fe0430 in __kernel_vsyscall ()
#1  0xb7b756d0 in raise () from /lib/tls/i686/cmov/libc.so.6
#2  0xb7b77098 in abort () from /lib/tls/i686/cmov/libc.so.6
#3  0xb7b6e5ce in __assert_fail () from /lib/tls/i686/cmov/libc.so.6
#4  0xb7e5df29 in pthread_mutex_lock () from 
/lib/tls/i686/cmov/libpthread.so.0
#5  0x0813fccb in ldap_pvt_thread_mutex_lock (mutex=0x8bc64dc) at 
thr_posix.c:296
#6  0xb7998e8e in syncprov_op_mod (op=0x8bc3690, rs=0x923f911c) at 
syncprov.c:1965
#7  0x08105bfd in overlay_op_walk (op=0x8bc3690, rs=0x923f911c, 
which=op_modify, oi=0x87e9d18, on=0x87eeef0) at backover.c:659
#8  0x08105e9a in over_op_func (op=0x8bc3690, rs=0x923f911c, 
which=op_modify) at backover.c:721
#9  0x08105fc7 in over_op_modify (op=0x8bc3690, rs=0x923f911c) at 
backover.c:760
#10 0x080a117e in fe_op_modify (op=0x8bc3690, rs=0x923f911c) at 
modify.c:301
#11 0x080a0a6d in do_modify (op=0x8bc3690, rs=0x923f911c) at modify.c:175
#12 0x08082a43 in connection_operation (ctx=0x923f9210, arg_v=0x8bc3690) 
at connection.c:1123
#13 0x08082f8b in connection_read_thread (ctx=0x923f9210, argv=0x12) at 
connection.c:1259
#14 0x0813eb0e in ldap_int_thread_pool_wrapper (xpool=0x87af8e8) at 
tpool.c:685
#15 0xb7e5c4ff in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#16 0xb7c2e49e in clone () from /lib/tls/i686/cmov/libc.so.6

Please let me know if i can provide additional information for you. (But 
please tell me how to do so, my gdb knowledge is fairly poor)

Regards,
Frank Offermanns