Re: [Qemu-devel] [PATCH v4 0/3] block: Fix unaligned bdrv_aio_write_zeroes

[Fam Zheng <famz@redhat.com>]

On Thu, 04/30 15:34, Kevin Wolf wrote:
> Am 27.04.2015 um 15:18 hat Fam Zheng geschrieben:
> > An unaligned zero write causes NULL deferencing in bdrv_co_do_pwritev. That
> > path is reachable from bdrv_co_write_zeroes and bdrv_aio_write_zeroes.
> > 
> > You can easily trigger through the former with qemu-io, as the test case added
> > by 61815d6e0aa. For bdrv_aio_write_zeroes, in common cases there's always a
> > format driver (which uses 512 alignment), so it would be much rarer to have
> > unaligned requests (only concerning top level here, when the request goes down
> > to bs->file, where for example the alignment is 4k, it would then be calling
> > bdrv_co_write_zeroes because it's in a coroutine).
> > 
> > fc3959e4669a1c fixed bdrv_co_write_zeroes but not bdrv_aio_write_zeroes.  The
> > lattern is the actually used one by device model. Revert the previous fix, do
> > it in bdrv_co_do_pwritev, to cover both paths.
> 
> Hi Fam,
> 
> Stefan's patch to split out block/io.c conflicts with this. Can you
> please rebase?

I'll do it.

Fam

> 
> Kevin
>