[Libguestfs] [PATCH libnbd] ublk: Add new nbdublk program

[Richard W.M. Jones]

On Wed, Aug 31, 2022 at 06:33:25PM +0800, Ming Lei wrote:
> On Wed, Aug 31, 2022 at 11:22:04AM +0100, Richard W.M. Jones wrote:
> > 
> > After running those tests for an hour or two I got a nasty kernel
> > memory corruption issue in the test VM, see attached.
> 
> >From the dmesg log, the direct issue is from zram.
> 
> The userspace ublksrv shouldn't trigger this kind of issue, and the only
> related code is to discard IO pages if they are idle for enough time via
> madvise(MADV_DONTNEED).
> 
> In the ublk driver side, we just pin and unpin pages, and it shouldn't
> be hard to verify if they work correctly . I will trace in that area.
> Except for pin & unpin pages, ublk driver doesn't play any other mm
> game.

In case it's an unrelated bug in the very new RC2 kernel I've started
another test which just uses a local (virtio-scsi) disk, to see if I
observe the same thing or not.

Rich.

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