Re: [PATCH 00/10] mm: various (urgent?) fixes

[Muchun Song <muchun.song@linux.dev>]

> On Oct 16, 2026, at 00:07, David Hildenbrand (Arm) <david@kernel.org> wrote:
> 
> Hi,
> 
> here are various MM fixes. The majority was reported by Josef at
> Anthrophic, the remainder was found while reviewing/overhauling them.
> 
> Two issues/fixes reported are not included, as we are discussing
> (better) alternatives on the list already.
> 
> I left most of the original commit messages as schloppy as they are: I
> don't particularly care as long as the code is in good shape and as long as
> they are not actively wrong. But I (and Mike) could not be stopped from
> overhauling at least some of them.
> 
> While I don't think there is anything too critical in here, I think this
> is a good opportunity to see how fast we can get pre-screened/pre-reviewed
> fixes upstream that might be security-related.
> 
> The majority are hugetlb + uffd issues, that are not actually that
> relevant for most installations. But all things that should just get
> fixed. Some uffd fixes need proper follow ups to fix some more of the
> root causes of leftover UFFD PTE bits (or proof that there are none
> remaining).
> 
> I ran some MM selftests and nothing popped up.
> 
> So let's try to get these upstream in a timely fashion.
> 
> Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
> ---
> David Hildenbrand (Arm) (4):
>      mm/hugetlb: fix use-after-free in hugetlb_mfill_atomic_pte()
>      mm/hugetlb: tolerate uffd bits set without uffd for PROT_NONE PTEs
>      mm/hugetlb: tolerate UFFD_WP markers outside uffd-wp VMAs
>      mm/mremap: fix calling fixup_hugetlb_reservations() on the wrong VMA
> 
> Josef Bacik (6):
>      mm/vma: don't leak the commit charge on mmap failure
>      mm/hugetlb: fix use-after-free of a new anon folio
>      mm/hugetlb: unmap the page where the other VMA maps it
>      mm/hugetlb: don't clear the resv_map of a VMA whose lock is held
>      mm/hugetlb: fix endless write fault on a leftover uffd bit
>      mm/hugetlb: don't leave a uffd-wp marker when zapping an RWP entry

HugeTLB is really nasty, while no new features are landing, we have a steady
stream of bug fixes coming in.

Thanks,
Muchun

> 
> mm/hugetlb.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++--------------
> mm/mremap.c  |  2 +-
> mm/vma.c     | 11 ++++++----
> 3 files changed, 62 insertions(+), 21 deletions(-)
> 
> ---
> 
> base-commit: 0fcb05b72344f40806cbe810de8872f1698bf053
> 
> change-id: 20261015-urgent_fixes-7112629346eb
> 
> --
> 
> Cheers,
> 
> David
>