From owner-freebsd-current Thu Jul 18 12: 9:46 2002 Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.FreeBSD.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id DA48A37B400; Thu, 18 Jul 2002 12:09:43 -0700 (PDT) Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by mx1.FreeBSD.org (Postfix) with ESMTP id 9027943E5E; Thu, 18 Jul 2002 12:09:43 -0700 (PDT) (envelope-from dillon@apollo.backplane.com) Received: from apollo.backplane.com (localhost [127.0.0.1]) by apollo.backplane.com (8.12.5/8.12.4) with ESMTP id g6IJ9hCV019461; Thu, 18 Jul 2002 12:09:43 -0700 (PDT) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.12.5/8.12.4/Submit) id g6IJ9hTq019460; Thu, 18 Jul 2002 12:09:43 -0700 (PDT) (envelope-from dillon) Date: Thu, 18 Jul 2002 12:09:43 -0700 (PDT) From: Matthew Dillon Message-Id: <200207181909.g6IJ9hTq019460@apollo.backplane.com> To: Alfred Perlstein Cc: John Baldwin , current@FreeBSD.ORG Subject: Re: Questions about kern_descrip.c References: <200207181840.g6IIe25G019269@apollo.backplane.com> <20020718185538.GJ77219@elvis.mu.org> Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG : :* Matthew Dillon [020718 11:40] wrote: :> :> fdalloc() does not reserve the descriptor number it :> returns, it simply finds a free slot and says 'this :> index is a free slot'. Even in the latest -current, :> fdalloc() releases the fdp lock when it goes to :> MALLOC so the race appears to still be present. : :This is true. I think one way to fix this is to preallocate :the 'struct file' you're going to put into the array and have :fdalloc() insert the created file instead of just finding a :slot. Problem is that it's a bunch of grunt work to do this. : :-- :-Alfred Perlstein [alfred@freebsd.org] :'Instead of asking why a piece of software is using "1970s technology," If you do this be careful in regards to open() and close() which might place the descriptor in a transitory state. You don't want another thread picking the descriptor up while it is in that state. -Matt Matthew Dillon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message