Threading experts?

[Jason Edmeades]

Hi,

I seem to have found a recreatable threading problem and I am not 
convinced it it wines fault either. Are there any experts here who want 
to offer any advice on where to go to persue this please?

Problem:
'wine appname' hangs when it creates one of its threads. The hang is 
inside pthread_create and control is never returned to the caller

Environment
uname -a returns kernel 2.4.21-0.13mdk, and its basically Mandrake Linux 
9.1 with no updates. Wine is cvs as of today, configured with --with-nptl

More info:
Looking through an strace, I can see a difference between a working and 
failing case, and it would appear there is a timing issue inside the 
pthread routines. However, I would normally expect it far more likely 
that it is a wine bug than a kernel / threading bug, so I dont really 
know how to proceed. I can recreate this about 95% of the time with one 
app and one app only, so I really suspect it to be a wine problem, but I 
just cant see why.

Here's a working case
===============
 (Note SY3 and SY4 are fixmes I added each side of the pthread_create)

394 issues a create thread.
[pid   394] write(2, "fixme:thread:SYSDEPS_SpawnThread"..., 
38fixme:thread:SYSDEPS_SpawnThread SY 3) = 38
[pid   394] rt_sigprocmask(SIG_SETMASK, NULL, [RTMIN], 8) = 0
[pid   394] write(12, 
"\240 at 4@\0\0\0\0\230,s@\240\177\v@\0000\20J\0\0\0\200\0"..., 148 
<unfinished ...>
:
398 is the pthread thread manager thread
[pid   398] getppid()                   = 394
[pid   398] read(10, 
"\240 at 4@\0\0\0\0\230,s@\240\177\v@\0000\20J\0\0\0\200\0"..., 148) = 148
[pid   398] clone(child_stack=0x4a102bd0, 
flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|0x21) = 400
:
It wakes up 394 to indicate it can continue
[pid   398] kill(394, SIGRTMIN)         = 0
:
[pid   394] <... write resumed> )       = 148
[pid   394] rt_sigprocmask(SIG_SETMASK, NULL, [RTMIN], 8) = 0
[pid   394] rt_sigsuspend([] <unfinished ...>
*** sigsuspend gets back a SIGRTMIN to wake it up.
[pid   394] --- SIGRTMIN (Unknown signal 32) @ 0 (0) ---
[pid   394] <... rt_sigsuspend resumed> ) = -1 EINTR (Interrupted system 
call)
[pid   394] sigreturn()                 = ? (mask now [RTMIN])
[pid   394] write(2, "fixme:thread:SYSDEPS_SpawnThread"..., 
38fixme:thread:SYSDEPS_SpawnThread SY 4

Failing case
========
394 issues a create thread.
[pid   394] write(2, "fixme:thread:SYSDEPS_SpawnThread"..., 
38fixme:thread:SYSDEPS_SpawnThread SY 3) = 38
[pid   394] rt_sigprocmask(SIG_SETMASK, NULL, [], 8) = 0
[pid   394] write(12, 
"\240 at 4@\0\0\0\0$&s@\240\177\v@\0000xJ\0\0\0\0\0\0\0\0`"..., 148 
<unfinished ...>
:
398 is the pthread thread manager thread
[pid   398] <... poll resumed> [{fd=10, events=POLLIN, revents=POLLIN}], 
1, 2000) = 1
[pid   398] getppid()                   = 394
[pid   398] read(10, 
"\240 at 4@\0\0\0\0$&s@\240\177\v@\0000xJ\0\0\0\0\0\0\0\0`"..., 148) = 148
[pid   398] clone(child_stack=0x4a782bd0, 
flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|0x21) = 401
:
It wakes up 394 to indicate it can continue
[pid   398] kill(394, SIGRTMIN)         = 0
:
(Now for the difference...)
[pid   394] <... write resumed> )       = 148
:
vvv What is this, and why is it getting the signal
[pid   394] --- SIGRTMIN (Unknown signal 32) @ 0 (0) ---
[pid   394] sigreturn()                 = ? (mask now [])
:
vvv Since the signal is absorbed already, suspend just hangs forever.
[pid   394] rt_sigprocmask(SIG_SETMASK, NULL, [], 8) = 0
[pid   394] rt_sigsuspend([] <unfinished ...>

Any help? Its really annoying
Jason