From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A735C10F14 for ; Thu, 10 Oct 2019 13:20:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5E9A9208C3 for ; Thu, 10 Oct 2019 13:20:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388172AbfJJNUA (ORCPT ); Thu, 10 Oct 2019 09:20:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:59340 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727852AbfJJNUA (ORCPT ); Thu, 10 Oct 2019 09:20:00 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 456B92064A; Thu, 10 Oct 2019 13:19:58 +0000 (UTC) Date: Thu, 10 Oct 2019 09:19:56 -0400 From: Steven Rostedt To: Peter Zijlstra Cc: x86@kernel.org, linux-kernel@vger.kernel.org, mhiramat@kernel.org, bristot@redhat.com, jbaron@akamai.com, torvalds@linux-foundation.org, tglx@linutronix.de, mingo@kernel.org, namit@vmware.com, hpa@zytor.com, luto@kernel.org, ard.biesheuvel@linaro.org, jpoimboe@redhat.com Subject: Re: [PATCH v3 5/6] x86/ftrace: Use text_poke() Message-ID: <20191010091956.48fbcf42@gandalf.local.home> In-Reply-To: <20191010092054.GR2311@hirez.programming.kicks-ass.net> References: <20191007081716.07616230.8@infradead.org> <20191007081945.10951536.8@infradead.org> <20191008104335.6fcd78c9@gandalf.local.home> <20191009224135.2dcf7767@oasis.local.home> <20191010092054.GR2311@hirez.programming.kicks-ass.net> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 10 Oct 2019 11:20:54 +0200 Peter Zijlstra wrote: > On Wed, Oct 09, 2019 at 10:41:35PM -0400, Steven Rostedt wrote: > > On Tue, 8 Oct 2019 10:43:35 -0400 > > Steven Rostedt wrote: > > > > > > > BTW, I'd really like to take this patch series through my tree. That > > > way I can really hammer it, as well as I have code that will be built > > > on top of it. > > > > I did a bit of hammering and found two bugs. One I sent a patch to fix > > (adding a module when tracing is enabled), but the other bug I > > triggered, I'm too tired to debug right now. But figured I'd mention it > > anyway. > > I'm thinking this should fix it... Just not sure this is the right plce, > then again, we're doing the same thing in jump_label and static_call, so > perhaps we should do it like this. > > --- a/arch/x86/kernel/alternative.c > +++ b/arch/x86/kernel/alternative.c > @@ -1230,10 +1230,15 @@ void text_poke_queue(void *addr, const v > * dynamically allocated memory. This function should be used when it is > * not possible to allocate memory. > */ > -void text_poke_bp(void *addr, const void *opcode, size_t len, const void *emulate) > +void __ref text_poke_bp(void *addr, const void *opcode, size_t len, const void *emulate) > { > struct text_poke_loc tp; > > + if (unlikely(system_state == SYSTEM_BOOTING)) { > + text_poke_early(addr, opcode, len); > + return; > + } We need a new system state. SYSTEM_UP ? (Arg, that name is confusing, SYSTEM_BOOTING_SMP?) Or perhaps just test num_online_cpus()? if (unlikely(system_state == SYSTEM_BOOTING && num_online_cpus() == 1) ? Because we can't do the above once we have more than one CPU running. -- Steve > + > text_poke_loc_init(&tp, addr, opcode, len, emulate); > text_poke_bp_batch(&tp, 1); > }