Programming

Try without setting SO_LINGER on the socdket and see if it behaves better.

Code:

SO_LINGER
    Waits to complete the close function if data is present. When this option is enabled and there is unsent data present when the close function is called, the calling application is blocked during the close function until the data is transmitted or the connection has timed out. The close function returns without blocking the caller. This option has meaning only for stream sockets.

Never mind.
linger->l_linger is 0. The correct behavior is that close does not block in
this case and the connected client will get a RST. Data is discarded.

Can you try an experiment with this thread detached and don't call pthread_join()?
What's a backtrace on the blocked thread look like in gdb? What's your signal handling
look like?

<Edit> If this looks familiar you may be getting bit by a kernel bug: Re: [PATCH -v2] fix for futex_wait signal stack corruption

no the problem is not with the threads, again it stucks on the accept.

If you are sure that accept() is this badly broken on FC8 then you should probably open a TT with the fedora folks. I don't think that's the core issue though...

Any multithreaded code can cause hard to troubleshoot issues when moved to
another platform or kernel version. Sounds like this is the case here.