Subject: Re: [PATCH] vhost: make msg padding explicit

From: "Michael S. Tsirkin" <[email-masked]>
Date: Wed, 2 May 2018 16:36:37 +0300

On Wed, May 02, 2018 at 02:28:09AM -0400, Kevin Easton wrote:
> On Tue, May 01, 2018 at 02:05:51PM -0400, David Miller wrote:
> > From: "Michael S. Tsirkin" <[email-masked]>
> > Date: Tue, 1 May 2018 20:19:19 +0300
> > 
> > > On Tue, May 01, 2018 at 11:28:22AM -0400, David Miller wrote:
> > >> From: "Michael S. Tsirkin" <[email-masked]>
> > >> Date: Fri, 27 Apr 2018 19:02:05 +0300
> > >> 
> > >> > There's a 32 bit hole just after type. It's best to
> > >> > give it a name, this way compiler is forced to initialize
> > >> > it with rest of the structure.
> > >> > 
> > >> > Reported-by: Kevin Easton <[email-masked]>
> > >> > Signed-off-by: Michael S. Tsirkin <[email-masked]>
> > >> 
> > >> Michael, will you be sending this directly to Linus or would you like
> > >> me to apply it to net or net-next?
> > >> 
> > >> Thanks.
> > > 
> > > I'd prefer you to apply it for net and cc stable if possible.
> > 
> > Ok, applied, and added to my -stable submission queue.
> 
> Hold on, this patch changes the layout for i386 (where there is
> no padding at all).  And it's part of UAPI.
> 
>     - Kevin
> 
> > 

Ouch.  True - and in particular the 32 bit ABI on 64 bit kernels doesn't
work at all. Hmm. It's relatively new and maybe there aren't any 32 bit
users yet. Thoughts?

-- 
MST