From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S270861AbTGVRca (ORCPT ); Tue, 22 Jul 2003 13:32:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S270883AbTGVRca (ORCPT ); Tue, 22 Jul 2003 13:32:30 -0400 Received: from crosslink-village-512-1.bc.nu ([81.2.110.254]:51964 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S270861AbTGVRca (ORCPT ); Tue, 22 Jul 2003 13:32:30 -0400 Subject: Re: pivot_root seems to be broken in 2.4.21-ac4 From: Alan Cox To: Jason Baron Cc: Rene Mayrhofer , vda@port.imtp.ilyichevsk.odessa.ua, Linux Kernel Mailing List In-Reply-To: References: Content-Type: text/plain Content-Transfer-Encoding: 7bit Organization: Message-Id: <1058895650.4161.23.camel@dhcp22.swansea.linux.org.uk> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.2 (1.2.2-5) Date: 22 Jul 2003 18:40:50 +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Maw, 2003-07-22 at 18:37, Jason Baron wrote: > > I tell init to re-execute itself (after pivot_root and thus from the new > > root fs), which causes init to close its old fds and open new ones from > > the new root fs with. This is necessary because init already runs as pid > > 1 when I start the root fs switching. Maybe something changed with the > > kernel process fds from 2.4.21-rc2 to 2.4.21-ac4 ? > > > > yes, see the addition of the unshare_files function in kernel/fork.c Shouldnt really have changed anything except for security exploits and threaded apps doing weird stuff. In normal situations the files count is one so we should actually be executing nothing more exciting that an atomic_inc/atomic_dec. I wonder what is going on here.