[kvm] Dolphin screen goes black opening Find dialog [mirclient: Caught exception at client library boundary (in mir_buffer_release) ... std::exception::what: error: use of MirBuffer when mir_buffer_is_valid() is false]

Checking on real hardware, I cannot reproduce this.

Relevant error messages: from unity8, when dolphin goes black:

[2017-02-20 17:59:28.580916] <ERROR> mirclient: Caught exception at client library boundary (in mir_buffer_release): /build/mir-rgB9wX/mir-0.26.1+17.04.20170209.1/src/client/error_buffer.cpp(75): Throw in function virtual void mir::client::ErrorBuffer::set_callback(MirBufferCallback, void*)
Dynamic exception type: boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<std::logic_error> >
std::exception::what: error: use of MirBuffer when mir_buffer_is_valid() is false

[2017-02-20 17:59:28.588928] <ERROR> mirclient: Caught exception at client library boundary (in mir_buffer_release): /build/mir-rgB9wX/mir-0.26.1+17.04.20170209.1/src/client/error_buffer.cpp(75): Throw in function virtual void mir::client::ErrorBuffer::set_callback(MirBufferCallback, void*)
Dynamic exception type: boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<std::logic_error> >
std::exception::what: error: use of MirBuffer when mir_buffer_is_valid() is false

and from dolphin itself: http://pastebin.ubuntu.com/24035218/

Interestingly QtUbuntu doesn't call mir_buffer_is_valid or mir_buffer_release itself. I don't see any evidence that is Qt is destroying/recreating its surface either. Odd

What is your KVM/Qemu configuration?

I used whatever virtual machine manager chose as default:

qemu-system-x86_64 -enable-kvm -name guest=Zesty,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-1-Zesty/master-key.aes -machine pc-i440fx-zesty,accel=kvm,usb=off,dump-guest-core=off -cpu SandyBridge -m 2500 -realtime mlock=off -smp 3,sockets=3,cores=1,threads=1 -uuid b0a26a36-075f-4f5d-9b8f-d874c11e7115 -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-1-Zesty/monitor.sock,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc,driftfix=slew -global kvm-pit.lost_tick_policy=discard -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=0x5.0x7 -device ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x5 -device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pci.0,addr=0x5.0x1 -device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pci.0,addr=0x5.0x2 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x6 -drive file=/home/gerry/Virtual Machines/zesty.qcow2,format=qcow2,if=none,id=drive-ide0-0-0 -device ide-hd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 -drive if=none,id
=drive-ide0-0-1,readonly=on -device ide-cd,bus=ide.0,unit=1,drive=drive-ide0-0-1,id=ide0-0-1 -netdev tap,fd=26,id=hostnet0 -device rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:90:6
1:1e,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev spicevmc,id=charchannel0,name=vdagent -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.spice.0 -spice port=5900,addr=127.0.0.1,disable-ticketing,image-compression=off,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 -device intel-hda,id=sound0,bus=pci.0,addr=0x4 -device hda-duplex
,id=sound0-codec0,bus=sound0.0,cad=0 -chardev spicevmc,id=charredir0,name=usbredir -device usb-redir,chardev=charredir0,id=redir0,bus=usb.0,port=1 -chardev spicevmc,id=charredir1,n
ame=usbredir -device usb-redir,chardev=charredir1,id=redir1,bus=usb.0,port=2 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x7 -msg timestamp=on

Syncing task from Mir.