From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: qemu-kvm: sigsegv at exit Date: Thu, 22 Oct 2009 14:00:15 +0200 Message-ID: <20091022120015.GA28836@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: kvm@vger.kernel.org, qemu-devel@nongnu.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:56473 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753267AbZJVMC2 (ORCPT ); Thu, 22 Oct 2009 08:02:28 -0400 Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: Hi! I'm sometimes getting segfaults when I kill qemu. This time I caught it when qemu was under gdb: Program received signal SIGSEGV, Segmentation fault. [Switching to Thread 0x411d0940 (LWP 14446)] 0x000000000040afb4 in qemu_mod_timer (ts=0x19f0fd0, expire_time=62275467335) at /home/mst/scm/qemu-kvm/vl.c:1009 1009 if ((alarm_timer->flags & ALARM_FLAG_EXPIRED) == 0) { (gdb) l 1004 ts->next = *pt; 1005 *pt = ts; 1006 1007 /* Rearm if necessary */ 1008 if (pt == &active_timers[ts->clock->type]) { 1009 if ((alarm_timer->flags & ALARM_FLAG_EXPIRED) == 0) { 1010 qemu_rearm_alarm_timer(alarm_timer); 1011 } 1012 /* Interrupt execution to force deadline recalculation. */ 1013 if (use_icount) (gdb) p alarm_timer $1 = (struct qemu_alarm_timer *) 0x0 (gdb) where #0 0x000000000040afb4 in qemu_mod_timer (ts=0x19f0fd0, expire_time=62275467335) at /home/mst/scm/qemu-kvm/vl.c:1009 #1 0x000000000041aadf in virtio_net_handle_tx (vdev=, vq=0x19f5af0) at /home/mst/scm/qemu-kvm/hw/virtio-net.c:696 #2 0x0000000000421669 in kvm_run (vcpu=0x19d46a0, env=0x19c2250) at /home/mst/scm/qemu-kvm/qemu-kvm.c:797 #3 0x00000000004216d6 in kvm_cpu_exec (env=0x83d0f8) at /home/mst/scm/qemu-kvm/qemu-kvm.c:1714 #4 0x0000000000422981 in ap_main_loop (_env=) at /home/mst/scm/qemu-kvm/qemu-kvm.c:1969 #5 0x000000377dc06367 in start_thread () from /lib64/libpthread.so.0 #6 0x000000377d0d30ad in clone () from /lib64/libc.so.6 (gdb) So this probably means that we have already run quit_timers: static void quit_timers(void) { alarm_timer->stop(alarm_timer); alarm_timer = NULL; } but kvm vcpu thread is still running. Not sure what the right fix is here: should we stop kvm after main loop has exited? -- MST