Re: [PATCH] vhost: fix vhost_dev_enable_notifiers() error case

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Jun 07, 2023 at 12:32:31PM +0300, Michael Tokarev wrote:
> 02.06.2023 19:27, Laurent Vivier wrote:
> > in vhost_dev_enable_notifiers(), if virtio_bus_set_host_notifier(true)
> > fails, we call vhost_dev_disable_notifiers() that executes
> > virtio_bus_set_host_notifier(false) on all queues, even on queues that
> > have failed to be initialized.
> > 
> > This triggers a core dump in memory_region_del_eventfd():
> > 
> >   virtio_bus_set_host_notifier: unable to init event notifier: Too many open files (-24)
> >   vhost VQ 1 notifier binding failed: 24
> >   .../softmmu/memory.c:2611: memory_region_del_eventfd: Assertion `i != mr->ioeventfd_nb' failed.
> > 
> > Fix the problem by providing to vhost_dev_disable_notifiers() the
> > number of queues to disable.
> > 
> > Fixes: 8771589b6f81 ("vhost: simplify vhost_dev_enable_notifiers")
> > Cc: longpeng2@huawei.com
> > Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> > ---
> >   hw/virtio/vhost.c | 65 ++++++++++++++++++++++++++---------------------
> >   1 file changed, 36 insertions(+), 29 deletions(-)
> 
> Is this one a candidate for -stable?
> 
> The diffstat is somewhat large but it is just moving bit of code around.

I'd say so, yes.

> Thanks,
> 
> /mjt