| Message ID | D9DE8DBB19F2A24080482022C1DE758302C319B8@dggemm509-mbs.china.huawei.com |
|---|---|
| State | New |
| Headers | show |
| Series | [Bug] virtio-blk: qemu will crash if hotplug virtio-blk device failed | expand |
On Tue, Oct 31, 2017 at 05:19:08AM +0000, linzhecheng wrote: > I found that hotplug virtio-blk device will lead to qemu crash. The author posted a patch in a separate email thread. Please see "[PATCH] fix: unrealize virtio device if we fail to hotplug it". > Re-production steps: > > 1. Run VM named vm001 > > 2. Create a virtio-blk.xml which contains wrong configurations: > <disk device="lun" rawio="yes" type="block"> > <driver cache="none" io="native" name="qemu" type="raw" /> > <source dev="/dev/mapper/11-dm" /> > <target bus="virtio" dev="vdx" /> > </disk> > > 3. Run command : virsh attach-device vm001 vm001 > > Libvirt will return err msg: > > error: Failed to attach device from blk-scsi.xml > > error: internal error: unable to execute QEMU command 'device_add': Please set scsi=off for virtio-blk devices in order to use virtio 1.0 > > it means hotplug virtio-blk device failed. > > 4. Suspend or shutdown VM will leads to qemu crash > > > > from gdb: > > > (gdb) bt > #0 object_get_class (obj=obj@entry=0x0) at qom/object.c:750 > #1 0x00007f9a72582e01 in virtio_vmstate_change (opaque=0x7f9a73d10960, running=0, state=<optimized out>) at /mnt/sdb/lzc/code/open/qemu/hw/virtio/virtio.c:2203 > #2 0x00007f9a7261ef52 in vm_state_notify (running=running@entry=0, state=state@entry=RUN_STATE_PAUSED) at vl.c:1685 > #3 0x00007f9a7252603a in do_vm_stop (state=RUN_STATE_PAUSED) at /mnt/sdb/lzc/code/open/qemu/cpus.c:941 > #4 vm_stop (state=state@entry=RUN_STATE_PAUSED) at /mnt/sdb/lzc/code/open/qemu/cpus.c:1807 > #5 0x00007f9a7262eb1b in qmp_stop (errp=errp@entry=0x7ffe63e25590) at qmp.c:102 > #6 0x00007f9a7262c70a in qmp_marshal_stop (args=<optimized out>, ret=<optimized out>, errp=0x7ffe63e255d8) at qmp-marshal.c:5854 > #7 0x00007f9a72897e79 in do_qmp_dispatch (errp=0x7ffe63e255d0, request=0x7f9a76510120, cmds=0x7f9a72ee7980 <qmp_commands>) at qapi/qmp-dispatch.c:104 > #8 qmp_dispatch (cmds=0x7f9a72ee7980 <qmp_commands>, request=request@entry=0x7f9a76510120) at qapi/qmp-dispatch.c:131 > #9 0x00007f9a725288d5 in handle_qmp_command (parser=<optimized out>, tokens=<optimized out>) at /mnt/sdb/lzc/code/open/qemu/monitor.c:3852 > #10 0x00007f9a7289d514 in json_message_process_token (lexer=0x7f9a73ce4498, input=0x7f9a73cc6880, type=JSON_RCURLY, x=36, y=17) at qobject/json-streamer.c:105 > #11 0x00007f9a728bb69b in json_lexer_feed_char (lexer=lexer@entry=0x7f9a73ce4498, ch=125 '}', flush=flush@entry=false) at qobject/json-lexer.c:323 > #12 0x00007f9a728bb75e in json_lexer_feed (lexer=0x7f9a73ce4498, buffer=<optimized out>, size=<optimized out>) at qobject/json-lexer.c:373 > #13 0x00007f9a7289d5d9 in json_message_parser_feed (parser=<optimized out>, buffer=<optimized out>, size=<optimized out>) at qobject/json-streamer.c:124 > #14 0x00007f9a7252722e in monitor_qmp_read (opaque=<optimized out>, buf=<optimized out>, size=<optimized out>) at /mnt/sdb/lzc/code/open/qemu/monitor.c:3894 > #15 0x00007f9a7284ee1b in tcp_chr_read (chan=<optimized out>, cond=<optimized out>, opaque=<optimized out>) at chardev/char-socket.c:441 > #16 0x00007f9a6e03e99a in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0 > #17 0x00007f9a728a342c in glib_pollfds_poll () at util/main-loop.c:214 > #18 os_host_main_loop_wait (timeout=<optimized out>) at util/main-loop.c:261 > #19 main_loop_wait (nonblocking=nonblocking@entry=0) at util/main-loop.c:515 > #20 0x00007f9a724e7547 in main_loop () at vl.c:1999 > #21 main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at vl.c:4877 > > Problem happens in virtio_vmstate_change which is called by vm_state_notify, > static void virtio_vmstate_change(void *opaque, int running, RunState state) > { > VirtIODevice *vdev = opaque; > BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); > VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); > bool backend_run = running && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK); > vdev->vm_running = running; > > if (backend_run) { > virtio_set_status(vdev, vdev->status); > } > > if (k->vmstate_change) { > k->vmstate_change(qbus->parent, backend_run); > } > > if (!backend_run) { > virtio_set_status(vdev, vdev->status); > } > } > > Vdev's parent_bus is NULL, so qdev_get_parent_bus(DEVICE(vdev)) will crash. > virtio_vmstate_change is added to the list vm_change_state_head at virtio_blk_device_realize(virtio_init), > but after hotplug virtio-blk failed, virtio_vmstate_change will not be removed from vm_change_state_head. > > > I apply a patch as follews: > > diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c > index 5884ce3..ea532dc 100644 > --- a/hw/virtio/virtio.c > +++ b/hw/virtio/virtio.c > @@ -2491,6 +2491,7 @@ static void virtio_device_realize(DeviceState *dev, Error **errp) > virtio_bus_device_plugged(vdev, &err); > if (err != NULL) { > error_propagate(errp, err); > + vdc->unrealize(dev, NULL); > return; > }
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 5884ce3..ea532dc 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -2491,6 +2491,7 @@ static void virtio_device_realize(DeviceState *dev, Error **errp) virtio_bus_device_plugged(vdev, &err); if (err != NULL) { error_propagate(errp, err); + vdc->unrealize(dev, NULL); return; }
I found that hotplug virtio-blk device will lead to qemu crash. Re-production steps: 1. Run VM named vm001 2. Create a virtio-blk.xml which contains wrong configurations: <disk device="lun" rawio="yes" type="block"> <driver cache="none" io="native" name="qemu" type="raw" /> <source dev="/dev/mapper/11-dm" /> <target bus="virtio" dev="vdx" /> </disk> 3. Run command : virsh attach-device vm001 vm001 Libvirt will return err msg: error: Failed to attach device from blk-scsi.xml error: internal error: unable to execute QEMU command 'device_add': Please set scsi=off for virtio-blk devices in order to use virtio 1.0 it means hotplug virtio-blk device failed. 4. Suspend or shutdown VM will leads to qemu crash from gdb: (gdb) bt #0 object_get_class (obj=obj@entry=0x0) at qom/object.c:750 #1 0x00007f9a72582e01 in virtio_vmstate_change (opaque=0x7f9a73d10960, running=0, state=<optimized out>) at /mnt/sdb/lzc/code/open/qemu/hw/virtio/virtio.c:2203 #2 0x00007f9a7261ef52 in vm_state_notify (running=running@entry=0, state=state@entry=RUN_STATE_PAUSED) at vl.c:1685 #3 0x00007f9a7252603a in do_vm_stop (state=RUN_STATE_PAUSED) at /mnt/sdb/lzc/code/open/qemu/cpus.c:941 #4 vm_stop (state=state@entry=RUN_STATE_PAUSED) at /mnt/sdb/lzc/code/open/qemu/cpus.c:1807 #5 0x00007f9a7262eb1b in qmp_stop (errp=errp@entry=0x7ffe63e25590) at qmp.c:102 #6 0x00007f9a7262c70a in qmp_marshal_stop (args=<optimized out>, ret=<optimized out>, errp=0x7ffe63e255d8) at qmp-marshal.c:5854 #7 0x00007f9a72897e79 in do_qmp_dispatch (errp=0x7ffe63e255d0, request=0x7f9a76510120, cmds=0x7f9a72ee7980 <qmp_commands>) at qapi/qmp-dispatch.c:104 #8 qmp_dispatch (cmds=0x7f9a72ee7980 <qmp_commands>, request=request@entry=0x7f9a76510120) at qapi/qmp-dispatch.c:131 #9 0x00007f9a725288d5 in handle_qmp_command (parser=<optimized out>, tokens=<optimized out>) at /mnt/sdb/lzc/code/open/qemu/monitor.c:3852 #10 0x00007f9a7289d514 in json_message_process_token (lexer=0x7f9a73ce4498, input=0x7f9a73cc6880, type=JSON_RCURLY, x=36, y=17) at qobject/json-streamer.c:105 #11 0x00007f9a728bb69b in json_lexer_feed_char (lexer=lexer@entry=0x7f9a73ce4498, ch=125 '}', flush=flush@entry=false) at qobject/json-lexer.c:323 #12 0x00007f9a728bb75e in json_lexer_feed (lexer=0x7f9a73ce4498, buffer=<optimized out>, size=<optimized out>) at qobject/json-lexer.c:373 #13 0x00007f9a7289d5d9 in json_message_parser_feed (parser=<optimized out>, buffer=<optimized out>, size=<optimized out>) at qobject/json-streamer.c:124 #14 0x00007f9a7252722e in monitor_qmp_read (opaque=<optimized out>, buf=<optimized out>, size=<optimized out>) at /mnt/sdb/lzc/code/open/qemu/monitor.c:3894 #15 0x00007f9a7284ee1b in tcp_chr_read (chan=<optimized out>, cond=<optimized out>, opaque=<optimized out>) at chardev/char-socket.c:441 #16 0x00007f9a6e03e99a in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0 #17 0x00007f9a728a342c in glib_pollfds_poll () at util/main-loop.c:214 #18 os_host_main_loop_wait (timeout=<optimized out>) at util/main-loop.c:261 #19 main_loop_wait (nonblocking=nonblocking@entry=0) at util/main-loop.c:515 #20 0x00007f9a724e7547 in main_loop () at vl.c:1999 #21 main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at vl.c:4877 Problem happens in virtio_vmstate_change which is called by vm_state_notify, static void virtio_vmstate_change(void *opaque, int running, RunState state) { VirtIODevice *vdev = opaque; BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); bool backend_run = running && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK); vdev->vm_running = running; if (backend_run) { virtio_set_status(vdev, vdev->status); } if (k->vmstate_change) { k->vmstate_change(qbus->parent, backend_run); } if (!backend_run) { virtio_set_status(vdev, vdev->status); } } Vdev's parent_bus is NULL, so qdev_get_parent_bus(DEVICE(vdev)) will crash. virtio_vmstate_change is added to the list vm_change_state_head at virtio_blk_device_realize(virtio_init), but after hotplug virtio-blk failed, virtio_vmstate_change will not be removed from vm_change_state_head. I apply a patch as follews: