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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 4AAD2C433EF for ; Thu, 23 Sep 2021 13:17:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2C71161164 for ; Thu, 23 Sep 2021 13:17:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241199AbhIWNTD (ORCPT ); Thu, 23 Sep 2021 09:19:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241192AbhIWNTD (ORCPT ); Thu, 23 Sep 2021 09:19:03 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5011FC061574; Thu, 23 Sep 2021 06:17:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=tmDonrWu05hjIRPkXFF1Mu4Nt+eEVaV44JNRiKNgNao=; b=H0DIJd9AONr/Qm3wvoF0U10Sc5 XFgyAlroSRTOuwagOj4JGeafBvbwpoXPZsRd2FbKAPO8IT7ZwbXEXu4KGzb9syWVpD8+pQrR7XIUr FES2cyryRjQicYQhJAjv7vI6rKwbRPPBImdlrHMHx5Tzds17FIkajXf0bjcYu5AmIs84znUDAu54F cH5Ee2yaOG9mILq9zqN28EJRyHp46PF5hdCTEqWQtrVU4KwuOXMexevjt6hkTrFVoDlC3BrAqG9B+ VO+2Xht0n5n0EHA8KtBFUB3cdN30c5XIds0QCp1lTwcZ7NNEMJEYNe2Q88A8hkCuWDcg1C9MqWD9A 7NsLjYPg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mTObH-005EcR-K7; Thu, 23 Sep 2021 13:17:20 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 20BF5300252; Thu, 23 Sep 2021 15:17:17 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id D0B5220251DC2; Thu, 23 Sep 2021 15:17:17 +0200 (CEST) Date: Thu, 23 Sep 2021 15:17:17 +0200 From: Peter Zijlstra To: Petr Mladek Cc: gor@linux.ibm.com, jpoimboe@redhat.com, jikos@kernel.org, mbenes@suse.cz, mingo@kernel.org, linux-kernel@vger.kernel.org, joe.lawrence@redhat.com, fweisbec@gmail.com, tglx@linutronix.de, hca@linux.ibm.com, svens@linux.ibm.com, sumanthk@linux.ibm.com, live-patching@vger.kernel.org, paulmck@kernel.org Subject: Re: [RFC][PATCH 3/7] sched,livepatch: Use task_try_func() Message-ID: References: <20210922110506.703075504@infradead.org> <20210922110836.065940560@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: live-patching@vger.kernel.org On Thu, Sep 23, 2021 at 02:05:00PM +0200, Petr Mladek wrote: > On Wed 2021-09-22 13:05:09, Peter Zijlstra wrote: > > +static int klp_check_task(struct task_struct *task, void *arg) > > Please, call this klp_check_and_switch_task() to make it clear > that it actually does the switch. Sure. > > + ret = task_try_func(task, klp_check_task, &old_name); > > + switch (ret) { > > + case -EBUSY: > > + pr_debug("%s: %s:%d is running\n", > > + __func__, task->comm, task->pid); > > + break; > > + case -EINVAL: > > + pr_debug("%s: %s:%d has an unreliable stack\n", > > + __func__, task->comm, task->pid); > > + break; > > + case -EADDRINUSE: > > + pr_debug("%s: %s:%d is sleeping on function %s\n", > > + __func__, task->comm, task->pid, old_name); > > + break; > > I would prefer to be on the safe side and catch error codes that might > eventually appear in the future. > > case 0: > /* success */ > break; case -EAGAIN: /* task_try_func() raced */ break; > default: > pr_debug("%s: Unknown error code (%d) when trying to switch %s:%d\n", > __func__, ret, task->comm, task->pid); > > > } Done.