open a connection, setup the connection with a mainloop using the code from test/test-utils.c. 2 threads use that connection and call dbus_connection_send_with_reply_and_block with a 5S timeout. When each thread make dbus call at high speed (> 800/S), in 1 minute, you can see one thread timeout occasionally , and very soon it will crash. This is 100% reproducible on 1.4.14.
attach the DBUS_VERBOSE log, I can see frequently it halt at [dbus-connection.c(1095):_dbus_connection_acquire_io_path] waiting for IO path to be acquirable.

could not find timeout 0x808a128 function 0x804d808 data 0x808bb50 to remove
*** glibc detected *** /home/qtu/ccsp_msg_bus/ptmsg: malloc(): memory corruption (fast): 0x0808c187 ***
======= Backtrace: =========
/lib/libc.so.6[0xb7e3a4]
/lib/libc.so.6[0xb81356]
/lib/libc.so.6(__libc_calloc+0xef)[0xb8248f]
/home/qtu/ccsp_msg_bus/ptmsg(dbus_malloc0+0x2b)[0x8064d3b]
/home/qtu/ccsp_msg_bus/ptmsg[0x805ca0e]
/home/qtu/ccsp_msg_bus/ptmsg[0x805c380]
/home/qtu/ccsp_msg_bus/ptmsg(dbus_connection_send_with_reply+0xab)[0x805570b]
/home/qtu/ccsp_msg_bus/ptmsg(dbus_connection_send_with_reply_and_block+0xb8)[0x8055a68]
/home/qtu/ccsp_msg_bus/ptmsg[0x804fffb]
/home/qtu/ccsp_msg_bus/ptmsg[0x804d158]
/home/qtu/ccsp_msg_bus/ptmsg[0x804d67c]
/lib/libc.so.6(__libc_start_main+0xe5)[0xb256e5]
/home/qtu/ccsp_msg_bus/ptmsg[0x804cde1]
======= Memory map: ========
00110000-00126000 r-xp 00000000 fd:00 1158061    /lib/libpthread-2.9.so
00126000-00127000 r--p 00015000 fd:00 1158061    /lib/libpthread-2.9.so
00127000-00128000 rw-p 00016000 fd:00 1158061    /lib/libpthread-2.9.so
00128000-0012a000 rw-p 00128000 00:00 0
0072e000-0072f000 r-xp 0072e000 00:00 0          [vdso]
00aea000-00b0a000 r-xp 00000000 fd:00 12597      /lib/ld-2.9.so
00b0b000-00b0c000 r--p 00020000 fd:00 12597      /lib/ld-2.9.so
00b0c000-00b0d000 rw-p 00021000 fd:00 12597      /lib/ld-2.9.so
00b0f000-00c7d000 r-xp 00000000 fd:00 1158060    /lib/libc-2.9.so
00c7d000-00c7f000 r--p 0016e000 fd:00 1158060    /lib/libc-2.9.so
00c7f000-00c80000 rw-p 00170000 fd:00 1158060    /lib/libc-2.9.so
00c80000-00c83000 rw-p 00c80000 00:00 0
00cb1000-00cee000 r-xp 00000000 08:11 34166      /home/qtu/work/ControlPlane/build/pc/bbhm/libdbus-1.so.3.5.7
00cee000-00cef000 rw-p 0003d000 08:11 34166      /home/qtu/work/ControlPlane/build/pc/bbhm/libdbus-1.so.3.5.7
00ded000-00df5000 r-xp 00000000 fd:00 1158062    /lib/librt-2.9.so
00df5000-00df6000 r--p 00007000 fd:00 1158062    /lib/librt-2.9.so
00df6000-00df7000 rw-p 00008000 fd:00 1158062    /lib/librt-2.9.so
07460000-0746d000 r-xp 00000000 fd:00 1155126    /lib/libgcc_s-4.3.2-20081105.so.1
0746d000-0746e000 rw-p 0000c000 fd:00 1155126    /lib/libgcc_s-4.3.2-20081105.so.1
08048000-08089000 r-xp 00000000 fd:00 141526     /home/qtu/ccsp_msg_bus/ptmsg
08089000-0808a000 rw-p 00040000 fd:00 141526     /home/qtu/ccsp_msg_bus/ptmsg
0808a000-080ab000 rw-p 0808a000 00:00 0          [heap]
b5600000-b5621000 rw-p b5600000 00:00 0
b5621000-b5700000 ---p b5621000 00:00 0
b57e9000-b57ea000 ---p b57e9000 00:00 0
b57ea000-b61ea000 rw-p b57ea000 00:00 0
b61ea000-b61eb000 ---p b61ea000 00:00 0
b61eb000-b6beb000 rw-p b61eb000 00:00 0
b6beb000-b6bec000 ---p b6beb000 00:00 0
b6bec000-b75ec000 rw-p b6bec000 00:00 0
b75ec000-b75ed000 ---p b75ec000 00:00 0
b75ed000-b7fef000 rw-p b75ed000 00:00 0
b7ffe000-b8000000 rw-p b7ffe000 00:00 0
bffeb000-c0000000 rw-p bffeb000 00:00 0          [stack]

Program received signal SIGABRT, Aborted.
0x0072e416 in __kernel_vsyscall ()
Missing separate debuginfos, use: debuginfo-install libgcc-4.3.2-7.i386
(gdb)  bt
#0  0x0072e416 in __kernel_vsyscall ()
#1  0x00b3a460 in raise () from /lib/libc.so.6
#2  0x00b3be28 in abort () from /lib/libc.so.6
#3  0x00b77fed in __libc_message () from /lib/libc.so.6
#4  0x00b7e3a4 in malloc_printerr () from /lib/libc.so.6
#5  0x00b81356 in _int_malloc () from /lib/libc.so.6
#6  0x00b8248f in calloc () from /lib/libc.so.6
#7  0x08064d3b in dbus_malloc0 (bytes=6) at dbus-memory.c:536
#8  0x0805ca0e in _dbus_timeout_new (interval=5000, handler=0x8055b60 <reply_handler_timeout>, data=0x808cda8, free_data_function=0) at dbus-timeout.c:70
#9  0x0805c380 in _dbus_pending_call_new_unlocked (connection=0x808bd00, timeout_milliseconds=5000, timeout_handler=0x8055b60 <reply_handler_timeout>)
    at dbus-pending-call.c:119
#10 0x0805570b in dbus_connection_send_with_reply (connection=0x808bd00, message=0x808da20, pending_return=0xbffff578, timeout_milliseconds=5000)
    at dbus-connection.c:3379
#11 0x08055a68 in dbus_connection_send_with_reply_and_block (connection=0x808bd00, message=0x808da20, timeout_milliseconds=5000, error=0xbffff5a8)
    at dbus-connection.c:3502
#12 0x0804fffb in CCSP_Message_Bus_Send_Msg_Block (bus_handle=0x808a428, message=0x808da20, timeout_mseconds=5000, result=0xbffff60c) at ccsp_message_bus.c:1416