Re: [boost] [fiber] Mac OS X

Subject: Re: [boost] [fiber] Mac OS X
From: Edd Dawson (lists_at_[hidden])
Date: 2011-01-30 10:19:11

On 1/29/2011 3:22 AM, Daniel Larimer wrote:

> Reason: KERN_INVALID_ADDRESS at address: 0x0000000000010fa0
> 0x00007fff80820f89 in makecontext ()
> (gdb) bt
> #0  0x00007fff80820f89 in makecontext ()
> #1  0x000000010001f3a3 in boost::contexts::context::impl_t::impl_t (this=0x100100210, fn=0x100016990<boost::fibers::detail::trampoline(void*)>, vp=0x100100190, stacksize=65536, nxt=0x1001001c0, alloc_=<value temporarily unavailable, due to optimizations>) at libs/context/src/context_ucontext.cpp:58
> #2  0x000000010001f183 in ~auto_ptr [inlined] () at /usr/include/c++/4.2.1/memory:59
> #3  0x000000010001f183 in boost::contexts::context::init_ (fn=0x100016990<boost::fibers::detail::trampoline(void*)>, nxt=0x1001001a0, vp=0x100100190, stacksize=65536, alloc=<value temporarily unavailable, due to optimizations>) at libs/context/src/context_ucontext.cpp:77
> #4  0x00000001000017db in boost::contexts::context::create<boost::contexts::protected_stack_allocator>  ()
> #5  0x0000000100001a96 in boost::fibers::detail::fiber_base::fiber_base<boost::contexts::protected_stack_allocator>  ()
> #6  0x0000000100001b65 in boost::fibers::detail::fiber_object<boost::_bi::bind_t<void, void (*)(), boost::_bi::list0>  >::fiber_object<boost::contexts::protected_stack_allocator>  ()
> #7  0x0000000100001bdd in boost::fibers::fiber::make_fiber_<boost::_bi::bind_t<void, void (*)(), boost::_bi::list0>, boost::contexts::protected_stack_allocator>  ()
> #8  0x0000000100001c54 in boost::fibers::fiber::fiber<boost::_bi::bind_t<void, void (*)(), boost::_bi::list0>, boost::contexts::protected_stack_allocator>  ()
> #9  0x00000001000010be in main ()

On OS X, it certainly used to be the case that you had to define _XOPEN_SOURCE 
before including <ucontext.h>. I notice that context_ucontext.cpp doesn't do 
this. When I bumped in to this in 2008 [1], it was already a known issue, but  I 
don't know if Apple has fixed it already.

I'd also suggest considering changing the default stack size to SIGSTKSZ rather 
than using an arbitrary(?) value of 65536. From the POSIX spec [2]:

"The value SIGSTKSZ is a system default specifying the number of bytes that 
would be used to cover the usual case when manually allocating an alternate 
stack area."

Kind regards,

Edd

[1] http://lists.apple.com/archives/darwin-dev/2008/Jan/msg00232.html
[2] http://pubs.opengroup.org/onlinepubs/009695399/functions/sigaltstack.html