On Fri, Jan 18, 2008 at 09:10:18PM +0000, Davide Libenzi wrote: > On Fri, 18 Jan 2008, Pierre Habouzit wrote: > > > Hi, > > > > I just came across a strange behavior of epoll that seems to > > contradict the documentation. Here is what happens: > > > > * I have two processes P1 and P2, P1 accept()s connections, and send the > > resulting file descriptors to P2 through a unix socket. > > > > * P2 registers the received socket in his epollfd. > > > > [time passes] > > > > * P2 is done with the socket and closes it > > > > * P2 gets events for the socket again ! > > > > > > Though the documentation says that if a process closes a file > > descriptor, it gets unregistered. And yes I'm sure that P2 doens't dup() > > the file descriptor. Though (because of a bug) it was still open in > > P1[0], hence the referenced socket still live at the kernel level. > > > > Of course the userland workaround is to force the EPOLL_CTL_DEL before > > the close, which I now do, but costs me a syscall where I wanted to > > spare one :| > > For epoll, a close is when the kernel file* is released (that is, when all > its instances are gone). > We could put a special handling in filp_close(), but I don't think is a > good idea, and we're better live with the current behaviour.
Okay, maybe updating the linux manpages to be more clear about that is the way to go then. Thanks -- ·O· Pierre Habouzit ··O [EMAIL PROTECTED] OOO http://www.madism.org
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