Hi all,

Today's linux-next merge of the mm-stable tree got a conflict in:

  mm/hugetlb.c

between commit:

  5596d9e8b553 ("mm/hugetlb: fix potential race in __update_and_free_hugetlb_folio()")

from Linus' tree and commit:

  a81fa1dc5db2 ("mm/hugetlb: fix potential race with try_memory_failure_hugetlb()")

from the mm-stable tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

-- 
Cheers,
Stephen Rothwell

diff --cc mm/hugetlb.c
index 43e1af868cfd,740df0b377aa..000000000000
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@@ -1725,6 -1722,20 +1722,13 @@@ static void __update_and_free_hugetlb_f
  		return;
  	}
  
+ 	/*
+ 	 * If we don't know which subpages are hwpoisoned, we can't free
+ 	 * the hugepage, so it's leaked intentionally.
+ 	 */
+ 	if (folio_test_hugetlb_raw_hwp_unreliable(folio))
+ 		return;
+ 
 -	/*
 -	 * Move PageHWPoison flag from head page to the raw error pages,
 -	 * which makes any healthy subpages reusable.
 -	 */
 -	if (unlikely(folio_test_hwpoison(folio)))
 -		folio_clear_hugetlb_hwpoison(folio);
 -
  	/*
  	 * If vmemmap pages were allocated above, then we need to clear the
  	 * hugetlb flag under the hugetlb lock.

On Mon, 15 Jul 2024 08:42:39 +1000 Stephen Rothwell <sfr@canb.auug.org.au> wrote:

> Hi all,
> 
> Today's linux-next merge of the mm-stable tree got a conflict in:
> 
>   mm/hugetlb.c
> 
> between commit:
> 
>   5596d9e8b553 ("mm/hugetlb: fix potential race in __update_and_free_hugetlb_folio()")
> 
> from Linus' tree and commit:
> 
>   a81fa1dc5db2 ("mm/hugetlb: fix potential race with try_memory_failure_hugetlb()")
> 
> from the mm-stable tree.
> 
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging.  You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
> 

Thanks.  This caused me grief.  

I removed a81fa1dc5db2 ("mm/hugetlb: fix potential race with
try_memory_failure_hugetlb()") from mm-stable and redid it against
mm-unstable.  It still has cc:stable so some merging work will be
needed when the stable tree maintainers get onto it.