From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753893Ab2IWHA4 (ORCPT ); Sun, 23 Sep 2012 03:00:56 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:57411 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753803Ab2IWHAa (ORCPT ); Sun, 23 Sep 2012 03:00:30 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Al Viro Cc: Greg Kroah-Hartman , Kay Sievers , "Serge E. Hallyn" , containers@lists.linux-foundation.org, Dave Hansen , linux-kernel@vger.kernel.org, Andy Whitcroft , sukadev@linux.vnet.ibm.com, Linus Torvalds , Alan Cox , Serge Hallyn References: <20120124220247.GA26353@hallyn.com> <20120124231601.GA4470@sergelap> <20120128195103.GA11299@sergelap> <87txup763i.fsf_-_@xmission.com> <87d31d75yj.fsf_-_@xmission.com> <20120923041906.GM13973@ZenIV.linux.org.uk> <87bogx5lg7.fsf@xmission.com> <20120923063038.GO13973@ZenIV.linux.org.uk> <20120923063445.GA26640@ZenIV.linux.org.uk> Date: Sun, 23 Sep 2012 00:00:19 -0700 In-Reply-To: <20120923063445.GA26640@ZenIV.linux.org.uk> (Al Viro's message of "Sun, 23 Sep 2012 07:34:45 +0100") Message-ID: <87pq5d441o.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=;;;mid=;;;hst=in01.mta.xmission.com;;;ip=98.207.153.68;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18WRcmsVASExfmjDHrIvSF1lXopSLEdCY4= X-SA-Exim-Connect-IP: 98.207.153.68 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 1.5 XMNoVowels Alpha-numberic number with no vowels * 0.1 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -3.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0000] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa02 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_XMDrugObfuBody_08 obfuscated drug references X-Spam-DCC: XMission; sa02 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Al Viro X-Spam-Relay-Country: Subject: Re: [PATCH 3/4] devpts: Make the newinstance option historical X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Fri, 06 Aug 2010 16:31:04 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Al Viro writes: > On Sun, Sep 23, 2012 at 07:30:38AM +0100, Al Viro wrote: >> On Sat, Sep 22, 2012 at 10:59:04PM -0700, Eric W. Biederman wrote: >> >> > The test: >> > >> + if (filp->f_vfsmnt->mnt_root == filp->f_dentry) >> > kicks in and no redirection is performed. >> >> Umm... OK, after the first round of recursion. Unless you bind /something/pts >> on /something. > > Other way round, of course... E.g. > mount --bind /dev /dev/pts > mount --bind /dev /dev/pts/pts > etc. enough times to overflow the kernel stack on recursion. Except of course I gave the wrong explanation. I did the open with O_PATH. Since O_PATH never calls open recursion is impossible. Eric