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

["Fernando Casas Schössow" <casasfernando@hotmail.com>]

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 <stefanha@gmail.com<mailto:stefanha@gmail.com>> 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