Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755850Ab3GQO5X (ORCPT ); Wed, 17 Jul 2013 10:57:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48331 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755301Ab3GQO5W (ORCPT ); Wed, 17 Jul 2013 10:57:22 -0400 Date: Wed, 17 Jul 2013 16:51:48 +0200 From: Oleg Nesterov To: Masami Hiramatsu Cc: Steven Rostedt , Peter Zijlstra , Frederic Weisbecker , linux-kernel@vger.kernel.org, Ingo Molnar , Arnaldo Carvalho de Melo , Andrew Morton , jovi.zhangwei@huawei.com, Jiri Olsa , Srikar Dronamraju Subject: Re: [RFC PATCH V2] tracing: Check f_dentry before accessing event_file/call in inode->i_private Message-ID: <20130717145148.GB7358@redhat.com> References: <20130705003223.GA4981@redhat.com> <20130709075519.2583.96462.stgit@mhiramat-M0-7522> <20130715181659.GA18505@redhat.com> <51E5FD33.4040604@hitachi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51E5FD33.4040604@hitachi.com> 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: 1337 Lines: 37 On 07/17, Masami Hiramatsu wrote: > > (2013/07/16 3:16), Oleg Nesterov wrote: > > On 07/09, Masami Hiramatsu wrote: > >> > >> To avoid this, when opening events/*/*/enable, we have to ensure > >> the dentry of the file is not unlinked yet, under event_mutex > >> is locked. > > > > Probably this can work, but I am starting to think that this ref > > count becomes toooooo complex.... > > Oleg, I agree that is a bit complex way to fix but it can fix. > > However, I think we should fix bugs first, because there are bugs. > I don't like to leave a bug in the kernel as it is, while we re- > start discussing new approach... And I am trying to fix the same problems, just _I think_ there is another and simpler approach. > So, I'd like to suggest you getting these fixes into ftrace as > first-aid treatment, and discuss your new series. Well, perhaps you are right... But this TRACE_EVENT_FL_REF_MASK code is new too, it is not that we only need a small fixlets to finish it. So I think that it makes sense to discuss the alternatives before we decide what exactly we should do. Oleg. -- 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/