From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753616AbbCBKA3 (ORCPT ); Mon, 2 Mar 2015 05:00:29 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:35761 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751602AbbCBKA1 (ORCPT ); Mon, 2 Mar 2015 05:00:27 -0500 Date: Mon, 2 Mar 2015 11:00:10 +0100 From: Peter Zijlstra To: Jiri Kosina Cc: mingo@kernel.org, rusty@rustcorp.com.au, mathieu.desnoyers@efficios.com, oleg@redhat.com, paulmck@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, andi@firstfloor.org, rostedt@goodmis.org, tglx@linutronix.de, Seth Jennings , Josh Poimboeuf , Masami Hiramatsu , Miroslav Benes , Petr Mladek Subject: Re: [RFC][PATCH 1/9] klp: Fix obvious RCU fail Message-ID: <20150302100010.GJ21418@twins.programming.kicks-ass.net> References: <20150228212447.381543289@infradead.org> <20150228213109.893891745@infradead.org> <20150302083530.GD5029@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 02, 2015 at 10:13:05AM +0100, Jiri Kosina wrote: > On Mon, 2 Mar 2015, Peter Zijlstra wrote: > > That said; I do have a follow up question on that code. So now you've > > successfully obtained an address in module space; but the moment you > > release that RCU-sched lock, the module can be gone. > > > > How does the whole live patching stuff deal with module removal during > > patching? > > We have a module notifier that serializes using klp_mutex with the > patching. Do you see a problem there? Should work I think; might be worth noting this in a comment above this lookup though.