Re: [RFC PATCH v2 1/2] mm/userfaultfd: fix memory corruption due to writeprotect

Peter Zijlstra
2021-01-05T14:27:46Z

On Tue, Jan 05, 2021 at 12:52:48AM -0800, Nadav Amit wrote:
> > On Jan 5, 2021, at 12:13 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > On Mon, Jan 04, 2021 at 02:24:38PM -0500, Andrea Arcangeli wrote:
> >> The problematic one not pictured is the one of the wrprotect that has
> >> to be running in another CPU which is also isn't picture above. More
> >> accurate traces are posted later in the thread.
> >
> > What thread? I don't seem to have discovered it yet, and the cover
> > letter from Nadav doesn't seem to have a msgid linking it either.
>
> Sorry for that:
>
> https://lore.kernel.org/lkml/X+K7JMrTEC9SpVIB@google.com/T/

Much reading later..

OK, go with the write-lock for now.