Re: [Boost-users] pthread, futex_wait hang

From: Peter Dimov (pdimov_at_[hidden])
Date: 2004-08-30 14:08:05

Matt Paindavoine. wrote:
> Hello,
>
> I have been using the spirit parser library, and other boost pieces
> (date, test, variant, ...), along with Mozilla.
> I recently merged in some parts of the application that were running
> separately, and the program started hanging.
> I did a bit of searching, but couldn't find anything significantly wrong,
> especially since the individual parts are working correctly.
> The problem seems to be related to threads, as the stack indicates (cf
> stack at the end), and as the strace output shows here:

[...]

> futex(0x4045b860, FUTEX_WAIT, 2, NULL)  = -1 EAGAIN (Resource
> temporarily
[...]

> #6  0x409c91fc in ~lightweight_mutex (this=0x819eb40) at
> lwm_pthreads.hpp:53 #7  0x409c9d24 in ~sp_counted_base_impl
>    (this=0x819eb40) at nsCXExpRecord.cpp:219
> #8  0x409c96e2 in boost::detail::sp_counted_base::destruct
>    (this=0x819eb40) at shared_count.hpp:115
> #9  0x409b2a7e in boost::detail::sp_counted_base::weak_release
>    (this=0x819eb40) at shared_count.hpp:173

This can happen if some parts of your multithreaded program were compiled 
without multithreading support (or vice versa). The pthread_mutex_destroy 
call in ~lightweight_mutex expects to find a pthread_mutex at &m_, but the 
shared_ptr was created by unthreaded code, and an empty lightweight_mutex 
got used.