[v3] libstdc++/24469

[Paolo Carlini]

Richard Guenther wrote:

>yes, I did study the PR in question (24469), but even from reading
>http://gcc.gnu.org/ml/libstdc++/2004-07/msg00095.html I cannot reproduce the
>failure in question by examining the source (I cannot find users of _M_thread_id
>in either mt_allocator.cc or mt_allocator.h apart from two setters on
>the v7 branch).
>  
>
Please look closer ;) (Considering mainline, for the moment) just grep 
for the various places where ._M_used[*] is changed. The point is simply 
that in one specific place, in _M_reclaim_block, the index is 
__block->_M_thread_id, which in general is != __thread_id, thus we are 
fiddling with another thread, not the one which is returning memory to 
the pool.

Paolo.