Re: [Qemu-devel] qemu process crash: Assertion failed: QLIST_EMPTY(&bs->tracked_requests)

[Fernando Casas Schössow]

Hello Stefan,

Thanks for your reply.
Fortunately I didn’t have the problem again and it’s not clear how it can be 
consistently reproduced. Daily backups are running as usual at the moment.

If there is anything I can do from my side or if you have any ideas to try to 
reproduce it let me know.

Thanks.

Fer

Sent from my iPhone

On 11 Dec 2017, at 12:56, Stefan Hajnoczi 
<address@hidden<mailto:address@hidden>> wrote:

On Thu, Dec 07, 2017 at 10:18:52AM +0000, Fernando Casas Schössow wrote:
Hi there,


Last night while doing a backup of a guest using the live snapshot mechanism 
the qemu process for the guest seem to had crashed.

The snapshot succeeded then the backup of the VM disk had place and also 
succeeded but the commit to the original disk after the backup seem to have 
failed.

The command I use in the script to take the snapshot is:


virsh snapshot-create-as --domain $VM backup-job.qcow2 --disk-only --atomic 
--quiesce --no-metadata


And then to commit back is:


virsh blockcommit $VM $TARGETDISK --base $DISKFILE --top $SNAPFILE --active 
--pivot


In the qemu log for the guest I found the following while the commit back was 
having place:


Assertion failed: QLIST_EMPTY(&bs->tracked_requests) 
(/home/buildozer/aports/main/qemu/src/qemu-2.10.1/block/mirror.c: mirror_run: 
884)

I'm running qemu 2.10.1 with libvirt 3.9.0 and kernel 4.9.65 on Alpine Linux 
3.7.

This is the complete guest info from the logs:


LC_ALL=C 
PATH=/bin:/sbin:/bin:/sbin:/usr/bin:/usr/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin
 HOME=/root USER=root QEMU_AUDIO_DRV=spice /usr/bin/qemu-system-x86_64 -name 
guest=DOCKER01,debug-threads=on -S -object 
secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-6-DOCKER01/master-key.aes
 -machine pc-i440fx-2.8,accel=kvm,usb=off,dump-guest-core=off -cpu 
IvyBridge,ss=on,vmx=on,pcid=on,hypervisor=on,arat=on,tsc_adjust=on,xsaveopt=on 
-drive 
file=/usr/share/edk2.git/ovmf-x64/OVMF_CODE-pure-efi.fd,if=pflash,format=raw,unit=0,readonly=on
 -drive 
file=/var/lib/libvirt/qemu/nvram/DOCKER01_VARS.fd,if=pflash,format=raw,unit=1 
-m 2048 -realtime mlock=off -smp 2,sockets=2,cores=1,threads=1 -uuid 
4705b146-3b14-4c20-923c-42105d47e7fc -no-user-config -nodefaults -chardev 
socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-6-DOCKER01/monitor.sock,server,nowait
 -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc,driftfix=slew 
-global kvm-pit.lost_tick_policy=delay -no-hpet -no-shutdown -global 
PIIX4_PM.disable_s3=1 -global PIIX4_PM.disable_s4=1 -boot strict=on -device 
ich9-usb-ehci1,id=usb,bus=pci.0,addr=0x4.0x7 -device 
ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x4 
-device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pci.0,addr=0x4.0x1 
-device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pci.0,addr=0x4.0x2 
-device ahci,id=sata0,bus=pci.0,addr=0x9 -device 
virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x5 -drive 
file=/storage/storage-ssd-vms/virtual_machines_ssd/docker01.qcow2,format=qcow2,if=none,id=drive-sata0-0-0,cache=none,aio=threads
 -device ide-hd,bus=sata0.0,drive=drive-sata0-0-0,id=sata0-0-0,bootindex=1 
-netdev tap,fd=33,id=hostnet0,vhost=on,vhostfd=35 -device 
virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:1c:af:ce,bus=pci.0,addr=0x3 
-chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 
-chardev 
socket,id=charchannel0,path=/var/lib/libvirt/qemu/channel/target/domain-6-DOCKER01/org.qemu.guest_agent.0,server,nowait
 -device 
virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.0
 -chardev spicevmc,id=charchannel1,name=vdagent -device 
virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel1,id=channel1,name=com.redhat.spice.0
 -spice port=5905,addr=127.0.0.1,disable-ticketing,seamless-migration=on 
-device 
qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,vram64_size_mb=0,vgamem_mb=16,max_outputs=1,bus=pci.0,addr=0x2
 -chardev spicevmc,id=charredir0,name=usbredir -device 
usb-redir,chardev=charredir0,id=redir0,bus=usb.0,port=2 -chardev 
spicevmc,id=charredir1,name=usbredir -device 
usb-redir,chardev=charredir1,id=redir1,bus=usb.0,port=3 -device 
virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x7 -object 
rng-random,id=objrng0,filename=/dev/random -device 
virtio-rng-pci,rng=objrng0,id=rng0,bus=pci.0,addr=0x8 -msg timestamp=on



I was running on qemu 2.8.1 for months and didn't have any problems with the 
backups but yesterday I updated to qemu 2.10.1 and I hit this problem last 
night.


Is this a bug? Any ideas will be appreciated.

Thanks for reporting this bug.  Can you reproduce it reliably?

Stefan