Re: [Qemu-devel] [Bug 1191606] Re: qemu crashes with iscsi initiator (libiscsi) when using virtio

[Stefan Hajnoczi <stefanha@gmail.com>]

On Tue, Jun 18, 2013 at 09:34:39PM -0700, ronnie sahlberg wrote:
> I can reproduce with current QEMU.
> 
> Ubuntu 13 crashes with if=virtio but if=ide is fine.
> 
> 
> But it seems dependent on the guest/kernel.
> 
> For example Fedora-18-x86_64-Live-Desktop.iso  installs and runs just
> fine, even with virtio
> But both ubuntu-12.04-desktop-amd64.iso or
> ubuntu-13.04-desktop-amd64.iso crash with if=virtio
> 
> 
> Stack backtrace I got is

The issue is not obvious to me yet but here some comments on the stack
trace:

> #0  0x00007f7a9e22d037 in __GI_raise (sig=sig@entry=6)
>     at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
> #1  0x00007f7a9e230698 in __GI_abort () at abort.c:90
> #2  0x00007f7aa0a93ec8 in qemu_ram_addr_from_host_nofail (
>     ptr=ptr@entry=0x2020202024008000) at /DATA/SRC/qemu-kvm/qemu/exec.c:1399
> #3  0x00007f7aa0a94a50 in address_space_unmap (as=<optimised out>,
>     buffer=0x2020202024008000, len=<optimised out>, is_write=<optimised out>,

Junk buffer address.

>     access_len=1) at /DATA/SRC/qemu-kvm/qemu/exec.c:2155
> #4  0x00007f7aa0a94bef in cpu_physical_memory_unmap (buffer=<optimised out>,
>     len=<optimised out>, is_write=<optimised out>, access_len=<optimised out>)
>     at /DATA/SRC/qemu-kvm/qemu/exec.c:2189
> #5  0x00007f7aa0ad7867 in virtqueue_fill (vq=vq@entry=0x7f7aa34277f0,
>     elem=elem@entry=0x7f7aa37ca328, len=1, idx=idx@entry=0)
>     at /DATA/SRC/qemu-kvm/qemu/hw/virtio/virtio.c:243

Unmapping req->elem.in_sg[0] (serial number buffer).

> #6  0x00007f7aa0ad79cf in virtqueue_push (vq=0x7f7aa34277f0,
>     elem=elem@entry=0x7f7aa37ca328, len=<optimised out>)
>     at /DATA/SRC/qemu-kvm/qemu/hw/virtio/virtio.c:279
> #7  0x00007f7aa0aa9989 in virtio_blk_req_complete (
>     req=req@entry=0x7f7aa37ca320, status=status@entry=0)
>     at /DATA/SRC/qemu-kvm/qemu/hw/block/virtio-blk.c:49
> #8  0x00007f7aa0aa9ffb in virtio_blk_handle_request (
>     req=req@entry=0x7f7aa37ca320, mrb=mrb@entry=0x7fff7a7b2060)
>     at /DATA/SRC/qemu-kvm/qemu/hw/block/virtio-blk.c:376

VIRTIO_BLK_T_GET_ID - the guest is querying the device's serial number.

Stefan