[Bug libgcj/29604] Race condition in ServerSocket.accept()

["ddaney at avtrex dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #4 from ddaney at avtrex dot com  2006-10-26 18:03 -------
Subject: Re:  Race condition in ServerSocket.accept()

tromey at gcc dot gnu dot org wrote:
> ------- Comment #3 from tromey at gcc dot gnu dot org  2006-10-26 17:58 -------
> Instead of directly calling accept we could select or poll on the fd.
> This would let us have a timeout or an interrupt or something.
> For all I know poll would react more gracefully to another thread
> closing the fd -- but I haven't tried that.
> 

The essence of the problem is that you can not temporarily drop a lock 
(as Object.wait() does) in a race free manner while entering the 
accept() system call.  Sticking a poll before the accept may in some 
cases narrow the window of the race, but it does not close it.

I was going to fix the problem in 15 Minutes, but now I think I need a 
day to mull it over.

This is the type of problem that keeps us sharp...

David Daney


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29604