Deadlock in +initialize with libojbc2

[Thomas Davie]

Hi all,

I'm hitting an issue with deadlocks in +initialize.  I'm using the latest (svn 
35399) libobjc2.  Gdb tells me this:

(gdb) info threads
  Id   Target Id         Frame 
* 2    Thread 0x7fffe2612700 (LWP 8878) "bds" 0x00007ffff65f9be4 in 
__lll_lock_wait () from /lib/x86_64-linux-gnu/libpthread.so.0
  1    Thread 0x7ffff7fe6000 (LWP 8875) "bds" 0x00007ffff65f9be4 in 
__lll_lock_wait () from /lib/x86_64-linux-gnu/libpthread.so.0
(gdb) thread 1
[Switching to thread 1 (Thread 0x7ffff7fe6000 (LWP 8875))]
#0  0x00007ffff65f9be4 in __lll_lock_wait () from 
/lib/x86_64-linux-gnu/libpthread.so.0
(gdb) bt
#0  0x00007ffff65f9be4 in __lll_lock_wait () from 
/lib/x86_64-linux-gnu/libpthread.so.0
#1  0x00007ffff65f5200 in _L_lock_928 () from 
/lib/x86_64-linux-gnu/libpthread.so.0
#2  0x00007ffff65f5099 in pthread_mutex_lock () from 
/lib/x86_64-linux-gnu/libpthread.so.0
#3  0x00007ffff6a96919 in create_dtable_for_class (class=0x7fffdc862900, 
root_dtable=0xae4ab0) at dtable.c:498
#4  0x00007ffff6a964b9 in objc_send_initialize (object=<optimized out>) at 
dtable.c:693
#5  0x00007ffff6a9e776 in objc_msg_lookup_internal (receiver=<optimized out>, 
selector=<optimized out>, sender=<optimized out>) at sendmsg2.c:73
#6  objc_msg_lookup_sender (receiver=<optimized out>, selector=<optimized out>, 
sender=<optimized out>) at sendmsg2.c:171
#7  0x00000000005a4678 in -[Move 
initWithAttack:withSoldier:againstTile:rolls:preAttackHP:preAttackPositions:preAttackBuffs:defenders:]
 (self=0x7fffdc862878, _cmd=0x9b5770, a=0x28e5908, s=0x2e0e478, 
#8  A bunch of my code all the way down to main.
(gdb) thread 2
[Switching to thread 2 (Thread 0x7fffe2612700 (LWP 8878))]
#0  0x00007ffff65f9be4 in __lll_lock_wait () from 
/lib/x86_64-linux-gnu/libpthread.so.0
(gdb) bt
#0  0x00007ffff65f9be4 in __lll_lock_wait () from 
/lib/x86_64-linux-gnu/libpthread.so.0
#1  0x00007ffff65f5200 in _L_lock_928 () from 
/lib/x86_64-linux-gnu/libpthread.so.0
#2  0x00007ffff65f5099 in pthread_mutex_lock () from 
/lib/x86_64-linux-gnu/libpthread.so.0
#3  0x00007ffff6a95fb8 in dtable_for_class (cls=<optimized out>, cls=<optimized 
out>, cls=<optimized out>) at ./dtable.h:66
#4  classHasDtable (cls=<optimized out>, cls=<optimized out>, cls=<optimized 
out>) at ./dtable.h:110
#5  mergeMethodsFromSuperclass (super=0x7ffff7d1a8e0, cls=<optimized out>, 
methods=0x65ea8f0) at dtable.c:444
#6  0x00007ffff6a9628d in add_method_list_to_class (cls=0x7ffff7d1a8e0, 
list=<optimized out>) at dtable.c:488
#7  0x00007ffff6a9aaa6 in class_addMethod (cls=0x7ffff7d1a8e0, name=<optimized 
out>, imp=0x7ffff77eac30 <-[NSGDate timeIntervalSince1970]>, types=<optimized 
out>) at runtime.c:191
#8  0x00007ffff794ec4f in GSObjCAddMethods (cls=0x7ffff7d1a8e0, list=0x65ea7a0, 
replace=0 '\000') at GSObjCRuntime.m:559
#9  0x00007ffff794f566 in GSObjCAddClassBehavior (receiver=0x7ffff7d1a8e0, 
behavior=0x7ffff7d1a810) at GSObjCRuntime.m:902
#10 0x00007ffff77eb116 in +[GSDateSingle initialize] (self=0x7ffff7d1a8e0, 
_cmd=<optimized out>) at NSDate.m:1517
#11 0x00007ffff6a965c6 in objc_send_initialize (object=<optimized out>) at 
dtable.c:733
#12 0x00007ffff6a96427 in objc_send_initialize (object=<optimized out>) at 
dtable.c:666
#13 0x00007ffff6a9e776 in objc_msg_lookup_internal (receiver=<optimized out>, 
selector=<optimized out>, sender=<optimized out>) at sendmsg2.c:73
#14 objc_msg_lookup_sender (receiver=<optimized out>, selector=<optimized out>, 
sender=<optimized out>) at sendmsg2.c:171
#15 0x00007ffff77e975b in +[NSDate distantFuture] (self=0x7ffff7d1a740, 
_cmd=<optimized out>) at NSDate.m:985
#16 0x00007ffff78af10d in +[NSRunLoop initialize] (self=0x7ffff7d5fc40, 
_cmd=<optimized out>) at NSRunLoop.m:697
#17 0x00007ffff6a965c6 in objc_send_initialize (object=<optimized out>) at 
dtable.c:733
#18 0x00007ffff6a9e776 in objc_msg_lookup_internal (receiver=<optimized out>, 
selector=<optimized out>, sender=<optimized out>) at sendmsg2.c:73
#19 objc_msg_lookup_sender (receiver=<optimized out>, selector=<optimized out>, 
sender=<optimized out>) at sendmsg2.c:171
#20 0x00000000004aa888 in -[DatabaseConnection runPingThread] (self=0x2a06698, 
_cmd=0x9b76b0) at Classes/Database/DatabaseConnection.m:120
#21 0x00007ffff786a655 in -[NSObject performSelector:withObject:] 
(self=<optimized out>, _cmd=<optimized out>, aSelector=0x9b76b0, 
anObject=0x7fffe2610500) at NSObject.m:2001
#22 0x00007ffff78e336e in -[NSThread main] (self=0x2a1c5b8, _cmd=<optimized 
out>) at NSThread.m:741
#23 0x00007ffff78e3b05 in nsthreadLauncher (thread=0x2a1c5b8) at NSThread.m:807
#24 0x00007ffff65f2efc in start_thread () from 
/lib/x86_64-linux-gnu/libpthread.so.0
#25 0x00007ffff632d59d in clone () from /lib/x86_64-linux-gnu/libc.so.6
#26 0x0000000000000000 in ?? ()

Does anyone have any idea why this might be happening?

Thanks

Tom Davie