From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: Re: [git pull] VFS - the first pile Date: Wed, 16 Mar 2011 13:15:02 +0000 Message-ID: <20110316131502.GS22723@ZenIV.linux.org.uk> References: <20110315213248.GL22723@ZenIV.linux.org.uk> <20110316061917.GA30195@dastard> <20110316065103.GP22723@ZenIV.linux.org.uk> <20110316072123.GR22723@ZenIV.linux.org.uk> <20110316130728.GB30866@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Theodore Tso , Dave Chinner , Linus Torvalds , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org To: Christoph Hellwig Return-path: Received: from zeniv.linux.org.uk ([195.92.253.2]:40494 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752648Ab1CPNPM (ORCPT ); Wed, 16 Mar 2011 09:15:12 -0400 Content-Disposition: inline In-Reply-To: <20110316130728.GB30866@infradead.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Wed, Mar 16, 2011 at 09:07:28AM -0400, Christoph Hellwig wrote: > On Wed, Mar 16, 2011 at 07:46:40AM -0400, Theodore Tso wrote: > > > > On Mar 16, 2011, at 3:21 AM, Al Viro wrote: > > > > > BTW, you want to update 005 in there - we are back to correct "maximum > > > is 40 symlinks total, 8 levels on nesting" for all syscalls. Add the > > > 41st symlink to your chain in testcase ;-) > > > > Unless there's a way to read out these limits, I'm not sure it's a good idea > > to add a test like that to xfstests --- it's too fragile since at some point > > we might change what those limits might be. > > > > Also, xfstests is primarily intended to be a file system level stress tester > > testing for correctness, and issues of whether we blow up on the 40th, > > 41st, or 42nd symlink seems more like an ABI issue --- and even there I'm > > not sure the ABI specification should be quite that detailed over what's > > allowed and not allowed. > > That's not what it tests anyway. It tests that we get ELOOP at some > point, and do not blow the stack. Which is someting that older Linux > code used to do. Yes. See patch upthread (or in for-linus). There are two parts in that test; *both* would actually trigger the b0rkage in the last commit of what got merged - the only reason why the first one (long chain) did not was that the limit got fixed and -ELOOP was no longer triggered. Symlink to itself did, of course, trigger it - complete with oops.