Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763182AbZCQKar (ORCPT ); Tue, 17 Mar 2009 06:30:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754756AbZCQKai (ORCPT ); Tue, 17 Mar 2009 06:30:38 -0400 Received: from fg-out-1718.google.com ([72.14.220.158]:10782 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754231AbZCQKah (ORCPT ); Tue, 17 Mar 2009 06:30:37 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=FTsmGqfFAcn+uOED+xbXqh+Q//eyf6B/l4HlBOkyz2fSk4Ku9L/nGlvRXkxkFCktIz 6aipxKLnikF6tYV9fEYn84TzZ8/hXc5o6gtp/H5tTQgPNVj2n+3YCIik68FYtUEH0X8k YRP/aOFSZ4D4gaEgrFZJQZNwumcfok8OBGDhE= Date: Tue, 17 Mar 2009 13:37:44 +0300 From: Alexey Dobriyan To: Al Viro Cc: Zhang Le , linux-kernel@vger.kernel.org, torvalds@osdl.org, alan@redhat.com Subject: Re: [PATCH] filp->f_pos not correctly updated in proc_task_readdir Message-ID: <20090317103744.GA2399@x200.localdomain> References: <1237185871-3343-1-git-send-email-r0bertz@gentoo.org> <20090316083457.GV28946@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090316083457.GV28946@ZenIV.linux.org.uk> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1744 Lines: 35 On Mon, Mar 16, 2009 at 08:34:57AM +0000, Al Viro wrote: > On Mon, Mar 16, 2009 at 02:44:31PM +0800, Zhang Le wrote: > > filp->f_pos only get updated at the end of the function. Thus d_off of those > > dirents who are in the middle will be 0, and this will cause a problem in > > glibc's readdir implementation, specifically endless loop. Because when overflow > > occurs, f_pos will be set to next dirent to read, however it will be 0, unless > > the next one is the last one. So it will start over again and again. > > Eh... Here's what's really going on: > > proc_..._fill_cache() API is rather kludgy and far too convoluted. In > particular, it calls filldir() and passes file->f_pos to it, expecting > the caller to update file->f_pos between the calls. proc_task_readdir() > uses that sucker, but doesn't update ->f_pos until the very end. As > the result, d_off of direntries produced by it gets screwed. > Broken-by: commit 61a28784028e6d55755e4d0f39bee8d9bf2ee8d9 > Author: Eric W. Biederman > Date: Mon Oct 2 02:18:49 2006 -0700 > > [PATCH] proc: Remove the hard coded inode numbers > > Patch is fine, but I'd rather rip the layers of ..._fill_cache() abstractions > out and see what falls out. Anyway, for -rc your variant is definitely the > way to go. Except this bit: fs/built-in.o: In function `proc_task_readdir': compr_zlib.c:(.text+0x434b8): undefined reference to `__cmpdi2' compr_zlib.c:(.text+0x434d4): undefined reference to `__cmpdi2' -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/