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[14.202.194.140]) by smtp.gmail.com with ESMTPSA id o7sm12882331pfa.37.2016.03.31.04.28.44 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 31 Mar 2016 04:28:45 -0700 (PDT) Received: by cotter.ozlabs.ibm.com (Postfix, from userid 1000) id 9E46DC00D3; Thu, 31 Mar 2016 22:28:40 +1100 (AEDT) From: Balbir Singh To: will.deacon@arm.com, kvm@vger.kernel.org Cc: mpe@ellerman.id.au, mikey@neuling.org, Balbir Singh Subject: [PATCH 4/5] Fix a race during exit processing Date: Thu, 31 Mar 2016 22:28:26 +1100 Message-Id: <1459423707-8956-5-git-send-email-bsingharora@gmail.com> X-Mailer: git-send-email 2.5.5 In-Reply-To: <1459423707-8956-1-git-send-email-bsingharora@gmail.com> References: <1459423707-8956-1-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=-7.8 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=ham 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);