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Date:   Fri, 30 Jun 2023 08:32:37 +0200
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     stable@vger.kernel.org, patches@lists.linux.dev,
        linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
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Subject: Re: [PATCH 6.4 00/29] 6.4.1-rc2 review
Message-ID: <2023063030-overgrown-unfunded-7523@gregkh>
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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