Re: [RFC PATCH 13/22] x86/fpu/xstate: Expand dynamic user state area on first use

[Peter Zijlstra]

On Tue, Oct 13, 2020 at 03:43:59PM -0700, Dave Hansen wrote:
> On 10/13/20 3:31 PM, Brown, Len wrote:
> > vmalloc() does not fail, and does not return an error, and so there is no concept
> > of returning a signal.
> 
> Well, the order-0 allocations are no-fail, as are the vmalloc kernel
> structures and the page tables that might have to be allocated.  But,
> that's not guaranteed to be in place *forever*.  I think we still need
> to check for and handle allocation failures, even if they're not known
> to be possible today.

Quite, on top of that, we could run out of vmalloc space (unlikely, but
sitll).

You really have to deal with vmalloc() failing.