From patchwork Mon Mar 10 20:35:38 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Srivatsa S. Bhat" X-Patchwork-Id: 3805891 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 76BF6BF540 for ; Mon, 10 Mar 2014 20:37:36 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 8FD3B202FF for ; Mon, 10 Mar 2014 20:37:35 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 95425202D1 for ; Mon, 10 Mar 2014 20:37:34 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WN6wu-0007RH-Fr; Mon, 10 Mar 2014 20:37:24 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WN6wp-0003KM-NO; Mon, 10 Mar 2014 20:37:19 +0000 Received: from e28smtp09.in.ibm.com ([122.248.162.9]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WN6wm-0003Hb-V4 for linux-arm-kernel@lists.infradead.org; Mon, 10 Mar 2014 20:37:18 +0000 Received: from /spool/local by e28smtp09.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 11 Mar 2014 02:06:52 +0530 Received: from d28dlp01.in.ibm.com (9.184.220.126) by e28smtp09.in.ibm.com (192.168.1.139) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; Tue, 11 Mar 2014 02:06:50 +0530 Received: from d28relay05.in.ibm.com (d28relay05.in.ibm.com [9.184.220.62]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id 1E425E0044 for ; Tue, 11 Mar 2014 02:10:34 +0530 (IST) Received: from d28av03.in.ibm.com (d28av03.in.ibm.com [9.184.220.65]) by d28relay05.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s2AKarZr9306334 for ; Tue, 11 Mar 2014 02:06:53 +0530 Received: from d28av03.in.ibm.com (localhost [127.0.0.1]) by d28av03.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s2AKZj93025505 for ; Tue, 11 Mar 2014 02:05:47 +0530 Received: from srivatsabhat.in.ibm.com ([9.79.217.186]) by d28av03.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id s2AKZg5Z025075; Tue, 11 Mar 2014 02:05:42 +0530 From: "Srivatsa S. Bhat" Subject: [PATCH v3 10/52] arm, kvm: Fix CPU hotplug callback registration To: paulus@samba.org, oleg@redhat.com, mingo@kernel.org, rjw@rjwysocki.net, rusty@rustcorp.com.au, peterz@infradead.org, tglx@linutronix.de, akpm@linux-foundation.org Date: Tue, 11 Mar 2014 02:05:38 +0530 Message-ID: <20140310203538.10746.25364.stgit@srivatsabhat.in.ibm.com> In-Reply-To: <20140310203312.10746.310.stgit@srivatsabhat.in.ibm.com> References: <20140310203312.10746.310.stgit@srivatsabhat.in.ibm.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14031020-2674-0000-0000-00000D1A6564 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140310_163717_488015_35A288F1 X-CRM114-Status: GOOD ( 13.54 ) X-Spam-Score: -4.2 (----) Cc: linux-arch@vger.kernel.org, ego@linux.vnet.ibm.com, walken@google.com, Russell King , kvm@vger.kernel.org, linux-pm@vger.kernel.org, Gleb Natapov , linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linuxppc-dev@ozlabs.org, linux-arm-kernel@lists.infradead.org, "Srivatsa S. Bhat" , tj@kernel.org, Paolo Bonzini , paulmck@linux.vnet.ibm.com, Ingo Molnar , Christoffer Dall X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Subsystems that want to register CPU hotplug callbacks, as well as perform initialization for the CPUs that are already online, often do it as shown below: get_online_cpus(); for_each_online_cpu(cpu) init_cpu(cpu); register_cpu_notifier(&foobar_cpu_notifier); put_online_cpus(); This is wrong, since it is prone to ABBA deadlocks involving the cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently with CPU hotplug operations). Instead, the correct and race-free way of performing the callback registration is: cpu_notifier_register_begin(); for_each_online_cpu(cpu) init_cpu(cpu); /* Note the use of the double underscored version of the API */ __register_cpu_notifier(&foobar_cpu_notifier); cpu_notifier_register_done(); Fix the kvm code in arm by using this latter form of callback registration. Cc: Christoffer Dall Cc: Gleb Natapov Cc: Russell King Cc: Ingo Molnar Cc: kvmarm@lists.cs.columbia.edu Cc: kvm@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Acked-by: Paolo Bonzini Signed-off-by: Srivatsa S. Bhat Acked-by: Christoffer Dall --- arch/arm/kvm/arm.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c index bd18bb8..f0e50a0 100644 --- a/arch/arm/kvm/arm.c +++ b/arch/arm/kvm/arm.c @@ -1051,21 +1051,26 @@ int kvm_arch_init(void *opaque) } } + cpu_notifier_register_begin(); + err = init_hyp_mode(); if (err) goto out_err; - err = register_cpu_notifier(&hyp_init_cpu_nb); + err = __register_cpu_notifier(&hyp_init_cpu_nb); if (err) { kvm_err("Cannot register HYP init CPU notifier (%d)\n", err); goto out_err; } + cpu_notifier_register_done(); + hyp_cpu_pm_init(); kvm_coproc_table_init(); return 0; out_err: + cpu_notifier_register_done(); return err; }