Re: [PATCH v7 03/14] x86/cet/ibt: Add IBT legacy code bitmap setup function

From: Florian Weimer
Date: Tue Jun 11 2019 - 03:28:54 EST


* Dave Hansen:

> My assumption has always been that these large, potentially sparse
> hardware tables *must* be mmap()'d with MAP_NORESERVE specified. That
> should keep them from being problematic with respect to overcommit.

MAP_NORESERVE pages still count towards the commit limit. The flag only
disables checks at allocation time, for this particular allocation. (At
least this was the behavior the last time I looked into this, I
believe.)

Not sure if this makes a difference here.

Thanks,
Florian