[PATCH v2 1/1] vhost: tolerate file descriptor in REM_MEM_REG msg

[Stephen Hemminger]

On Fri, 31 Jul 2026 08:19:07 +0000
"Bathija, Pravin" <Pravin.Bathija at dell.com> wrote:

> > > While the immediate motivation was libblkio, the spec's compatibility
> > > clause was written for exactly this situation — any front-end could
> > > make the same mistake. QEMU's libvhost-user reference implementation  
> > already tolerates it (see vu_rem_mem_reg).
> >
> > Which does not change that I dislike such compat.  
> 
> I couldn't agree with you more.  The libblkio fix is ready and will stop sending the fd.
> In an ideal world we'd fix libblkio and move on,  but there are already several released versions
> of libblkio in the wild that exhibit this behavior.  Users pairing those with a current DPDK will hit
> a broken connection with no obvious workaround.

IMHO security safety trumps the specification in this case.
Although it might help to document this somewhere and add a better message.