From patchwork Mon Mar 21 07:17:29 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Education Directorate X-Patchwork-Id: 8629801 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 281C49F8A8 for ; Mon, 21 Mar 2016 07:18:25 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5AF7420270 for ; Mon, 21 Mar 2016 07:18:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8D3B1202B8 for ; Mon, 21 Mar 2016 07:18:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752739AbcCUHSU (ORCPT ); Mon, 21 Mar 2016 03:18:20 -0400 Received: from mail-pf0-f195.google.com ([209.85.192.195]:34336 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752601AbcCUHSM (ORCPT ); Mon, 21 Mar 2016 03:18:12 -0400 Received: by mail-pf0-f195.google.com with SMTP id n5so28678027pfn.1 for ; Mon, 21 Mar 2016 00:18:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=AX6M7mqXQuwG+gevJ+x4Fz8ZvHguchESDc1p3RQytiY=; b=Pg4glAZseJobdE3uHBObO+h5HOzETXXrwr8vgVA0hEYRqZIhKuABdFVUaUIM3kFZi2 o+uXSqMou6pOQuOkHZ1mJXkA+TLmLhZSQ8crcs9HSbwlpkDoDaRxwPAAPrDP8VoY3eps TFXaWp2qwZZZ3q+PqLmZgpr1KOuqrtY/EfZesT2+UcQn+5xRJpWKVYD5Fzmig6xPJNjo MOWYNN4OVcU8i8yDkZs90APpLxGQ8dwJ69zzhMNdUxbIPRFndlkW7EqtAbwB0UbKqKTp udaYJlz9tJD5YMuEl9zTx4REmJL7KHzDERVE2HB7Ew499TcQF73iDYNNlBAu9Q8xYyRR KSZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=AX6M7mqXQuwG+gevJ+x4Fz8ZvHguchESDc1p3RQytiY=; b=nOQBKAAfgDfCjrr0oIutrWTkEjAxX2fWH9syv0Nmez/kAT6B6A4wPVSyaDV4UPHe1r cIJ63pwi/4smFjX+lTKrD0ECOkoNHXe3hSsuRxL7bgw9WKr35plwL91iPnWKU0d4uYmm Gs4+l3HTcjnYe7NsDhdU8UYZoUQ+P+EMyqdNP41pVzACIr8tjMqYRyi7I0moWdxrwsQ5 cCnQzw1DYYYstV0mk9aBMcBR/a2lcSuWJDQp52uFxnd8TeU0Ny9o0ukK9bpTl14OapQ3 0luonYk9veNtYdhMlY/JQFo+oOxE9d77gAIW5E6ROG46kTyQfRzpCsibjonmEBx5RSQ2 YvrA== X-Gm-Message-State: AD7BkJJF9zBt5cuoMgEcKtf4j3psznxqhLIktXAChsOA3bSMNKffpppddU6rr3OSvh5EHQ== X-Received: by 10.66.119.202 with SMTP id kw10mr42765699pab.110.1458544691506; Mon, 21 Mar 2016 00:18:11 -0700 (PDT) Received: from cotter.ozlabs.ibm.com ([122.99.82.10]) by smtp.gmail.com with ESMTPSA id xn8sm37966338pab.15.2016.03.21.00.18.09 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 21 Mar 2016 00:18:10 -0700 (PDT) Received: by cotter.ozlabs.ibm.com (Postfix, from userid 1000) id EAC6BC01F1; Mon, 21 Mar 2016 18:18:06 +1100 (AEDT) From: Balbir Singh To: will.deacon@arm.com, kvm@vger.kernel.org Cc: penberg@kernel.org, mpe@ellerman.id.au, mikey@neuling.org, aik@ozlabs.ru, Balbir Singh Subject: [PATCH 3/4] Fix a race during exit processing Date: Mon, 21 Mar 2016 18:17:29 +1100 Message-Id: <1458544650-31416-4-git-send-email-bsingharora@gmail.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1458544650-31416-1-git-send-email-bsingharora@gmail.com> References: <1458544650-31416-1-git-send-email-bsingharora@gmail.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, T_DKIM_INVALID, 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 Fix a race, described below lkvm stop ... handle_stop kvm_cpu__reboot kvm_cmd_run_exit vcpus exit ... dev_exit ... ioport__unregister ..serial... kvm__pause --> br_write_lock pthread_kill But the thread is already dead above. We mark the cpus as dying so that kvm_pause does nothing. This should not break any semantics Signed-off-by: Balbir Singh --- builtin-run.c | 3 +++ kvm.c | 5 +++++ 2 files changed, 8 insertions(+) diff --git a/builtin-run.c b/builtin-run.c index 17b1428..cdc7158 100644 --- a/builtin-run.c +++ b/builtin-run.c @@ -58,6 +58,7 @@ __thread struct kvm_cpu *current_kvm_cpu; static int kvm_run_wrapper; bool do_debug_print = false; +int kvm_cmd_exit; static const char * const run_usage[] = { "lkvm run [] []", @@ -648,6 +649,7 @@ static void kvm_cmd_run_exit(struct kvm *kvm, int guest_ret) { compat__print_all_messages(); + kvm_cmd_exit = 1; init_list__exit(kvm); if (guest_ret == 0 && do_debug_print) @@ -659,6 +661,7 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix) int ret = -EFAULT; struct kvm *kvm; + kvm_cmd_exit = 0; kvm = kvm_cmd_run_init(argc, argv); if (IS_ERR(kvm)) return PTR_ERR(kvm); diff --git a/kvm.c b/kvm.c index 1081072..53cf0e2 100644 --- a/kvm.c +++ b/kvm.c @@ -33,6 +33,8 @@ #define DEFINE_KVM_EXIT_REASON(reason) [reason] = #reason +extern int kvm_cmd_exit; + const char *kvm_exit_reasons[] = { DEFINE_KVM_EXIT_REASON(KVM_EXIT_UNKNOWN), DEFINE_KVM_EXIT_REASON(KVM_EXIT_EXCEPTION), @@ -435,6 +437,9 @@ void kvm__pause(struct kvm *kvm) if (!kvm->cpus[0] || kvm->cpus[0]->thread == 0) return; + if (kvm_cmd_exit) + return; + mutex_lock(&pause_lock); pause_event = eventfd(0, 0);