From mboxrd@z Thu Jan 1 00:00:00 1970 From: david ahern Subject: soft lockup in kvm_flush_remote_tlbs Date: Wed, 24 Oct 2007 17:00:54 -0600 Message-ID: <471FCEA6.6000903@cisco.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org I am trying, unsuccessfully so far, to get a vm running with 4 cpus. It is failing with a soft lockup: BUG: soft lockup detected on CPU#3! [] softlockup_tick+0x98/0xa6 [] update_process_times+0x39/0x5c [] smp_apic_timer_interrupt+0x5c/0x64 [] apic_timer_interrupt+0x1f/0x24 [] kvm_flush_remote_tlbs+0xce/0xdb [kvm] [] kvm_mmu_pte_write+0x1f2/0x368 [kvm] [] emulator_write_emulated_onepage+0x73/0xe6 [kvm] [] x86_emulate_insn+0x20d8/0x3348 [kvm] [] x86_decode_insn+0x624/0x872 [kvm] [] emulate_instruction+0x12b/0x258 [kvm] [] handle_exception+0x163/0x23f [kvm_intel] [] kvm_handle_exit+0x70/0x8a [kvm_intel] [] kvm_vcpu_ioctl_run+0x234/0x339 [kvm] [] kvm_vcpu_ioctl+0x0/0xa8f [kvm] [] kvm_vcpu_ioctl+0xbd/0xa8f [kvm] [] save_i387+0x23f/0x273 [] __next_cpu+0x12/0x21 [] find_busiest_group+0x177/0x462 [] setup_sigcontext+0x10d/0x190 [] get_page_from_freelist+0x96/0x310 [] get_page_from_freelist+0x2a6/0x310 [] flush_tlb_others+0x83/0xb3 [] flush_tlb_page+0x74/0x77 [] set_page_dirty_balance+0x8/0x35 [] do_wp_page+0x3a5/0x3bd [] dequeue_signal+0x2d/0x9c [] __handle_mm_fault+0x81b/0x87b [] kvm_vcpu_ioctl+0x0/0xa8f [kvm] [] do_ioctl+0x1c/0x5d [] vfs_ioctl+0x24a/0x25c [] sys_ioctl+0x48/0x5f [] syscall_call+0x7/0xb I am working with kvm-48, but also tried the 20071020 snapshot. The stuck code is kvm_flush_remote_tlbs(): while (atomic_read(&completed) != needed) { cpu_relax(); barrier(); } which I take to mean one of the CPUs is not ack'ing the TLB flush request. Is this is a known bug and any options to correct it? It works fine with 2 vcpus, but for a comparison with xen I'd like to get the vm working with 4. Host stats: OS: RHEL5 Processors: 2-Core 2 Duos (4 processors) KVM: kvm-48 and kvm-20071020-1 snapshot rpms QEMU command: qemu-kvm -boot c -localtime -hda /opt/kvm/images/cucm.img -m 1536 -smp 4 -serial file:/tmp/serial.log -net nic,macaddr=00:1a:4b:34:74:52,model=rtl8139 -net tap,ifname=tap0,script=/bin/true -vnc :2 -monitor stdio thanks, david ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/