Re: [Qemu-devel] dataplane degradation in 2.1

[Fam Zheng <famz@redhat.com>]

On Wed, 07/09 20:50, Andrey Korolyov wrote:
> Hello,
> 
> I`ve observed an immediate crash running tagged -rc1 with
> virtio-blk(675879f6f3c9463e103735a4e41e9deb0bee9b39). Please take a
> look on attached backtrace, hope that the fix still can made its way
> to 2.1. 1.6 works well with same config, so it`s clearly a regression.

This one should fix it:

http://lists.nongnu.org/archive/html/qemu-devel/2014-07/msg01531.html

Fam

> /usr/bin/qemu-system-x86_64 -name Windows2008R2 -S -machine pc-i440fx-2.1,accel=kvm,usb=off -m 4096 -realtime mlock=off -smp 2,sockets=1,cores=2,threads=2 -numa node,nodeid=0,cpus=0,mem=4096 -uuid 16e64e7e-2582-3236-c93b-ab37828325ea -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/Windows2008R2.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime -no-shutdown -boot strict=on -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x3 -drive file=/dev/virtmachines/win2008r2,if=none,id=drive-virtio-disk0,format=raw,cache=none,aio=native -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev socket,id=charchannel0,path=/var/lib/libvirt/qemu/win2008r2.sock,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.1 -device usb-tablet,id=input0 -vnc 127.0.0.1:0 -device cirrus-vga,id=video0,bus=pci.0,addr=0x2 -cpu qemu64,hv_relaxed -set device.virtio-disk0.config-wce=off -set device.virtio-disk0.scsi=off -set device.virtio-disk0.x-data-plane=on -msg timestamp=on

> Program received signal SIGSEGV, Segmentation fault.
> [Switching to Thread 0x7f79a8bfe700 (LWP 11306)]
> 0x00007f79badf323f in virtio_blk_rw_complete (opaque=0x7f79bb9606a0, ret=0) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/hw/block/virtio-blk.c:99
> 99          bdrv_acct_done(req->dev->bs, &req->acct);
> (gdb) thread apply all bt
> 
> Thread 5 (Thread 0x7f79aa753700 (LWP 11302)):
> #0  0x00007f79b4a87727 in ioctl () from /lib64/libc.so.6
> #1  0x00007f79bade24d9 in kvm_vcpu_ioctl (cpu=cpu@entry=0x7f79bba17eb0, type=type@entry=44672) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/kvm-all.c:1845
> #2  0x00007f79bade2615 in kvm_cpu_exec (cpu=cpu@entry=0x7f79bba17eb0) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/kvm-all.c:1714
> #3  0x00007f79badcdd2c in qemu_kvm_cpu_thread_fn (arg=0x7f79bba17eb0) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/cpus.c:874
> #4  0x00007f79b7589f3a in start_thread () from /lib64/libpthread.so.0
> #5  0x00007f79b4a8fc3d in clone () from /lib64/libc.so.6
> 
> Thread 4 (Thread 0x7f79a9f52700 (LWP 11303)):
> #0  0x00007f79b4a87727 in ioctl () from /lib64/libc.so.6
> #1  0x00007f79bade24d9 in kvm_vcpu_ioctl (cpu=cpu@entry=0x7f79bba53760, type=type@entry=44672) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/kvm-all.c:1845
> #2  0x00007f79bade2615 in kvm_cpu_exec (cpu=cpu@entry=0x7f79bba53760) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/kvm-all.c:1714
> #3  0x00007f79badcdd2c in qemu_kvm_cpu_thread_fn (arg=0x7f79bba53760) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/cpus.c:874
> #4  0x00007f79b7589f3a in start_thread () from /lib64/libpthread.so.0
> #5  0x00007f79b4a8fc3d in clone () from /lib64/libc.so.6
> 
> Thread 3 (Thread 0x7f79a8bfe700 (LWP 11306)):
> #0  0x00007f79badf323f in virtio_blk_rw_complete (opaque=0x7f79bb9606a0, ret=0) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/hw/block/virtio-blk.c:99
> #1  0x00007f79bb029a62 in bdrv_co_em_bh (opaque=0x7f789400dc30) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/block.c:4666
> #2  0x00007f79bb021597 in aio_bh_poll (ctx=ctx@entry=0x7f79bba37e90) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/async.c:81
> #3  0x00007f79bb032d05 in aio_poll (ctx=0x7f79bba37e90, blocking=blocking@entry=true) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/aio-posix.c:188
> #4  0x00007f79baea67b7 in iothread_run (opaque=0x7f79bbc18728) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/iothread.c:41
> #5  0x00007f79b7589f3a in start_thread () from /lib64/libpthread.so.0
> #6  0x00007f79b4a8fc3d in clone () from /lib64/libc.so.6
> 
> Thread 2 (Thread 0x7f789b7ff700 (LWP 11307)):
> #0  0x00007f79b758dd0c in pthread_cond_wait () from /lib64/libpthread.so.0
> #1  0x00007f79bb07fcb9 in qemu_cond_wait (cond=cond@entry=0x7f79bbc17e20, mutex=mutex@entry=0x7f79bbc17e50) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/util/qemu-thread-posix.c:135
> #2  0x00007f79bb01c95b in vnc_worker_thread_loop (queue=queue@entry=0x7f79bbc17e20) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/ui/vnc-jobs.c:222
> #3  0x00007f79bb01cd30 in vnc_worker_thread (arg=0x7f79bbc17e20) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/ui/vnc-jobs.c:323
> #4  0x00007f79b7589f3a in start_thread () from /lib64/libpthread.so.0
> #5  0x00007f79b4a8fc3d in clone () from /lib64/libc.so.6
> 
> Thread 1 (Thread 0x7f79bac87980 (LWP 11301)):
> #0  0x00007f79b4a86116 in ppoll () from /lib64/libc.so.6
> #1  0x00007f79bb031b19 in ppoll (__ss=0x0, __timeout=0x7fffa40e26e0, __nfds=<optimized out>, __fds=<optimized out>) at /usr/include/bits/poll2.h:77
> #2  qemu_poll_ns (fds=<optimized out>, nfds=<optimized out>, timeout=timeout@entry=510000000) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/qemu-timer.c:319
> #3  0x00007f79bb030f04 in os_host_main_loop_wait (timeout=510000000) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/main-loop.c:229
> #4  main_loop_wait (nonblocking=<optimized out>) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/main-loop.c:484
> #5  0x00007f79bad9eb9d in main_loop () at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/vl.c:2010
> #6  main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at /var/tmp/portage/app-emulation/qemu-2.1.0/work/qemu-2.1.0/vl.c:4530