Re: [PATCH 6.4 00/29] 6.4.1-rc2 review

[Greg Kroah-Hartman]

On Thu, Jun 29, 2023 at 11:20:45PM -0700, Linus Torvalds wrote:
> On Thu, 29 Jun 2023 at 22:59, Greg Kroah-Hartman
> <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> >     gup: add warning if some caller would seem to want stack expansion
> 
> Did you decide to take that one after all?

For now, yes.

> It's not exactly wrong, and it might help find any odd cases, but I do
> suspect you can get syzbot etc to trigger the warning. It's designed
> to find crazy users, and syzbot is - pretty much by definition and by
> design - one of the craziest out there.

I think the "crazy users" reports might be triggered sooner with stable
updates than from your tree as well, so this might be a early-warning
type system.  I am pretty sure at least one "distro" has enabled it in
their kernel already as well.

But if this starts triggering a bunch of warnings, and they are causing
problems, I'll drop it (and recommend you revert it in your tree too.)

I wanted to be "warning compatible" here for now to ensure the backports
were working properly.

thanks,

greg k-h