On 23.11.22 00:48, Mike Kravetz wrote:
On 11/22/22 15:03, Andrew Morton wrote:
On Tue, 22 Nov 2022 13:59:25 -0400 Jason Gunthorpe <jgg@xxxxxxxxxx> wrote:
While that's certainly valid, it's not the common use case with
hugetlb pages.
FWIW, I did check with our product teams and they do not knowingly make use
of private mappings without write. Of course, that is only a small and
limited sample size.
Yeah, if it is only this case I'm comfortable as well
So.... I am to slap a cc:stable on this patch and we're all good?
I think we will also need a Fixes tag. There are two options for this:
1) In this patch David rightly points out
"I assume this has been broken at least since 2014, when mm/gup.c came to
life. I failed to come up with a suitable Fixes tag quickly."
So, we could go with some old gup commit.
2) One of the benefits of this patch is silencing the warning introduced
by 1d8d14641fd9 ("mm/hugetlb: support write-faults in shared mappings").
So, we could use this for the tag. It is also more in line with David's
suggestion to "backport it into 6.0/6.1 to fix the warning".
My suggestion would be to use 1d8d14641fd9 for the fixes tag. However,
David may have a better suggestion/idea.
Right, in an ideal world we'd backport this patch here to the dawn of
time where hugetlb + gup came to life and FOLL_FORCE was not properly fenced
of for hugetlb.
However, such a patch is not really stable-worthy I guess. So I'm fine
with "fixing the warning introduced for finding such previously wrong
behavior" instead.
Fixes: 1d8d14641fd9 ("mm/hugetlb: support write-faults in shared mappings")
Cc: <stable@xxxxxxxxxxxxxxx>
--
Thanks,
David / dhildenb
