Re: [Boost-bugs] [Boost C++ Libraries] #5763: Segmentation fault in ASIO signal handler

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #5763: Segmentation fault in ASIO signal handler
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-08-08 13:23:12

#5763: Segmentation fault in ASIO signal handler
-------------------------------------------+--------------------------------
  Reporter:  Vladislav <phprus@…>          |       Owner:  chris_kohlhoff
      Type:  Patches                       |      Status:  new           
 Milestone:  To Be Determined              |   Component:  asio          
   Version:  Boost 1.47.0                  |    Severity:  Problem       
Resolution:                                |    Keywords:                
-------------------------------------------+--------------------------------

Comment (by chris_kohlhoff):

 I was able to reproduce the issue, and I believe the correct fix is to
 apply the following change to
 asio/include/asio/detail/gcc_x86_fenced_block.hpp:

 {{{
 @@ -43,8 +43,12 @@ public:
  private:
    static int barrier()
    {
 -    int r = 0;
 -    __asm__ __volatile__ ("xchgl %%eax, %0" : "=m" (r) : : "memory",
 "cc");
 +    int r = 0, m = 1;
 +    __asm__ __volatile__ (
 +        "xchgl %0, %1" :
 +        "=r"(r), "=m"(m) :
 +        "0"(1), "m"(m) :
 +        "memory", "cc");
      return r;
    }
  };
 }}}

 Can you please try this change and let me know if it also corrects the
 issue for you.

 Note that using the gcc_sync_fenced_block class does improve performance
 slightly, so I will also look to include your patch in the near future.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/5763#comment:7>
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