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@linuxfoundation.org wrote:
Linus Torvalds torvalds@linux-foundation.org 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