singal get lost while shuting down Apache

Hi everyone.
I'm developing an Apache 2.0.52 module that executed on Linux
2.4.9-e.3smp.
The module starts a new thread for each child process that does some
work and then waits on a condition variable for a signal. The signal is
sent when the Apache calls the callback method for the destruction of
the pool on the child process.
>From some reason the signal gets lost, and the thread does not exit
cleanly, which causes the Apache to generate the following core dump
for each child process:

#0 0x4011ed87 in pthread_mutex_lock () from /lib/libpthread.so.0
#1 0x4022b4b8 in free () from /lib/libc.so.6
#2 0x4010f6e9 in apr_allocator_destroy (allocator=0x811f080)
at apr_pools.c:109
#3 0x40110241 in apr_pool_destroy (pool=0x8169228) at apr_pools.c:780
#4 0x0807f40c in clean_child_exit (code=0) at prefork.c:192
#5 0x401213fb in sigaction () from /lib/libpthread.so.0
#6 0x401d8a28 in killpg () from /lib/libc.so.6
#7 0x40120c19 in pthread_kill_other_threads_np () from
/lib/libpthread.so.0
#8 0x4011cddc in pthread_cond_wait () from /lib/libpthread.so.0
#9 0x4035fc11 in ot::ConditionVariable::wait(ot::RecursiveMutex&) (
this=0x811f114, mutex=@0x811f0f4) at base/ConditionVariable.cpp:174
#10 0x40033976 in ChukuThread::run() (this=0x811f128)
at ContextPerServer.cpp:43
#11 0x4036705a in ot::Thread::doRun() (this=0x811f128) at
base/Thread.cpp:211
#12 0x40366eae in OpenTopThreadFunc (pArg=0x811f128) at
base/Thread.cpp:190
#13 0x4011dfaf in pthread_exit () from /lib/libpthread.so.0


I'd be glad if someone could help me with ideas how to signal the
waiting thread, or find another way to kill it.

Thanks,
Yaron.

steingold@gmail.com wrote:
> Hi everyone.
> I'm developing an Apache 2.0.52 module that executed on Linux
> 2.4.9-e.3smp.
> The module starts a new thread for each child process that does some
> work

Apache uses APR threads. Running threads other than through APR in
your module is going to need lots of care (on linux, APR threads are
implemented using pthreads).

> and then waits on a condition variable for a signal. The signal is

What signal? Not one of the signals Apache uses itself?

> I'd be glad if someone could help me with ideas how to signal the
> waiting thread, or find another way to kill it.

Use APR threads. Get cross-platform portability for free!

--
Nick Kew

Nick Kew wrote:
> steingold@gmail.com wrote:
> > Hi everyone.
> > I'm developing an Apache 2.0.52 module that executed on Linux
> > 2.4.9-e.3smp.
> > The module starts a new thread for each child process that does some
> > work
>
> Apache uses APR threads. Running threads other than through APR in
> your module is going to need lots of care (on linux, APR threads are
> implemented using pthreads).
>
> > and then waits on a condition variable for a signal. The signal is
>
> What signal? Not one of the signals Apache uses itself?
>
> > I'd be glad if someone could help me with ideas how to signal the
> > waiting thread, or find another way to kill it.
>
> Use APR threads. Get cross-platform portability for free!
>
> --
> Nick Kew

I've also tried using the APR signals, mutexes and threads but the
signal still gets lost.

I used the APR's apr_thread_cond_signal function that does not have a
signal number as a parameter.

the functions I used were :
apr_thread_cond_create
apr_thread_mutex_create
apr_thread_create
apr_thread_cond_wait

Yaron