[Bug libstdc++/54172] [4.7 Regression] __cxa_guard_acquire thread-safety issue

[bkoz at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54172

--- Comment #14 from Benjamin Kosnik <bkoz at gcc dot gnu.org> 2012-09-10 05:08:15 UTC ---
Author: bkoz
Date: Mon Sep 10 05:08:07 2012
New Revision: 191125

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=191125
Log:
2012-09-09  Thiago Macieira  <thiago.macieira@intel.com>

    PR libstdc++/54172
        * libsupc++/guard.cc (__cxa_guard_acquire): Exit the loop earlier if
        we detect that another thread has had success. Don't compare_exchange
        from a finished state back to a waiting state. Comment.


Modified:
    branches/gcc-4_7-branch/libstdc++-v3/ChangeLog
    branches/gcc-4_7-branch/libstdc++-v3/libsupc++/guard.cc

--- Comment #15 from Benjamin Kosnik <bkoz at gcc dot gnu.org> 2012-09-10 05:08:51 UTC ---
In 4.7-branch