From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751333Ab3FDUA5 (ORCPT ); Tue, 4 Jun 2013 16:00:57 -0400 Received: from mx1.redhat.com ([209.132.183.28]:16771 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751017Ab3FDUAz (ORCPT ); Tue, 4 Jun 2013 16:00:55 -0400 Date: Tue, 4 Jun 2013 21:57:00 +0200 From: Oleg Nesterov To: Al Viro Cc: "Eric W. Biederman" , Andrew Morton , Michal Hocko , Sergey Dyasly , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 4/4] proc: avoid ->f_pos overflows in proc_task_readdir() paths Message-ID: <20130604195700.GA31933@redhat.com> References: <20130603190705.GA11517@redhat.com> <877giarg81.fsf@xmission.com> <20130604171435.GA20416@redhat.com> <20130604173917.GB13110@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130604173917.GB13110@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 On 06/04, Al Viro wrote: > > On Tue, Jun 04, 2013 at 07:14:35PM +0200, Oleg Nesterov wrote: > > > There is another bug in here as well that we may return really crazy > > > things in the case of seek simultaneous with readdir. > > > > i_mutex? both vfs_readdir() and default_llseek() take it... Anyway, this > > is another issue. > > That's part of the reasons for the series I've mentioned (vfs.git#experimental); > seriously, check that up. Will do... but so far I am confused. I do not see how they could race (I mean /proc/pid/task only). OK, OK, the usage of ->f_pos in sys_getdents() looks "obviously wrong", but this is another story? And "put f_pos in a local variable" can't help. But if you meant other problems with readdir in general, then I seem to understand, thanks. Oleg.