Re: [Qemu-block] [Qemu-devel] [PULL 08/17] block: Assert no write requests under BDRV_O_INCOMING

[Kevin Wolf]

Am 18.02.2016 um 17:03 hat Laurent Vivier geschrieben:
> Hi,
> 
> this commit breaks incoming migration case:
> 
> qemu-system-ppc64 XXX -incoming tcp:0:4444
> qemu-system-ppc64: .../qemu/block/io.c:1304: bdrv_co_do_pwritev:
> Assertion `!(bs->open_flags & 0x0800)' failed.
> 
> Without "-incoming", the same command line boots fine.
> 
> Are you aware of the problem?

No, and with no other command line options it works for me:

    $ ppc64-softmmu/qemu-system-ppc64 -incoming tcp::4444

I have also tested somewhat more realistic cases on x86 (including
performing actual migrations) before committing the patch, so it's not
generally broken.

Can you please give the full command line and the stack backtrace? I
think you're seeing a bug where some PPC hardware tries to read (or
access anyway) the image before the migration has completed. This is for
obvious reasons wrong (the contents may still change until the VM is
handed over).

Kevin