From: Alistair Popple <apopple@nvidia.com>
To: <linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
Peter Xu <peterx@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>,
Nadav Amit <nadav.amit@gmail.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Hugh Dickins <hughd@google.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Jerome Glisse <jglisse@redhat.com>,
"Matthew Wilcox" <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>, <peterx@redhat.com>,
David Hildenbrand <david@redhat.com>,
Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH v6 03/23] mm: Check against orig_pte for finish_fault()
Date: Thu, 16 Dec 2021 16:01:47 +1100 [thread overview]
Message-ID: <6260997.DYpkEd5BTb@nvdebian> (raw)
In-Reply-To: <20211115075522.73795-4-peterx@redhat.com>
On Monday, 15 November 2021 6:55:02 PM AEDT Peter Xu wrote:
> We used to check against none pte and in those cases orig_pte should always be
> none pte anyway.
Is that always true? From what I can see in handle_pte_fault() orig_pte only
gets initialised in the !pmd_none() case so might not be pte_none.
> This change prepares us to be able to call do_fault() on !none ptes. For
> example, we should allow that to happen for pte marker so that we can restore
> information out of the pte markers.
>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
> mm/memory.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 04662b010005..d5966d9e24c3 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -4052,7 +4052,7 @@ vm_fault_t finish_fault(struct vm_fault *vmf)
> vmf->address, &vmf->ptl);
> ret = 0;
> /* Re-check under ptl */
> - if (likely(pte_none(*vmf->pte)))
> + if (likely(pte_same(*vmf->pte, vmf->orig_pte)))
> do_set_pte(vmf, page, vmf->address);
> else
> ret = VM_FAULT_NOPAGE;
>
next prev parent reply other threads:[~2021-12-16 5:02 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-15 7:54 [PATCH v6 00/23] userfaultfd-wp: Support shmem and hugetlbfs Peter Xu
2021-11-15 7:55 ` [PATCH v6 01/23] mm: Introduce PTE_MARKER swap entry Peter Xu
2021-12-03 3:30 ` Alistair Popple
2021-12-03 4:21 ` Peter Xu
2021-12-03 5:35 ` Alistair Popple
2021-12-03 6:45 ` Peter Xu
2021-12-07 2:12 ` Alistair Popple
2021-12-07 2:30 ` Peter Xu
2021-11-15 7:55 ` [PATCH v6 02/23] mm: Teach core mm about pte markers Peter Xu
2021-11-15 7:55 ` [PATCH v6 03/23] mm: Check against orig_pte for finish_fault() Peter Xu
2021-12-16 5:01 ` Alistair Popple [this message]
2021-12-16 5:38 ` Peter Xu
2021-12-16 5:50 ` Peter Xu
2021-12-16 6:23 ` Alistair Popple
2021-12-16 7:06 ` Peter Xu
2021-12-16 7:45 ` Alistair Popple
2021-12-16 8:04 ` Peter Xu
2021-11-15 7:55 ` [PATCH v6 04/23] mm/uffd: PTE_MARKER_UFFD_WP Peter Xu
2021-12-16 5:18 ` Alistair Popple
2021-12-16 5:45 ` Peter Xu
2021-11-15 7:55 ` [PATCH v6 05/23] mm/shmem: Take care of UFFDIO_COPY_MODE_WP Peter Xu
2021-11-15 7:55 ` [PATCH v6 06/23] mm/shmem: Handle uffd-wp special pte in page fault handler Peter Xu
2021-12-16 5:56 ` Alistair Popple
2021-12-16 6:17 ` Peter Xu
2021-12-16 6:30 ` Alistair Popple
2021-11-15 7:55 ` [PATCH v6 07/23] mm/shmem: Persist uffd-wp bit across zapping for file-backed Peter Xu
2021-11-15 8:00 ` [PATCH v6 08/23] mm/shmem: Allow uffd wr-protect none pte for file-backed mem Peter Xu
2021-11-15 8:00 ` [PATCH v6 09/23] mm/shmem: Allows file-back mem to be uffd wr-protected on thps Peter Xu
2021-11-15 8:01 ` [PATCH v6 10/23] mm/shmem: Handle uffd-wp during fork() Peter Xu
2021-11-15 8:01 ` [PATCH v6 11/23] mm/hugetlb: Introduce huge pte version of uffd-wp helpers Peter Xu
2021-11-15 8:01 ` [PATCH v6 12/23] mm/hugetlb: Hook page faults for uffd write protection Peter Xu
2021-11-15 8:01 ` [PATCH v6 13/23] mm/hugetlb: Take care of UFFDIO_COPY_MODE_WP Peter Xu
2021-11-15 8:02 ` [PATCH v6 14/23] mm/hugetlb: Handle UFFDIO_WRITEPROTECT Peter Xu
2021-11-15 8:02 ` [PATCH v6 15/23] mm/hugetlb: Handle pte markers in page faults Peter Xu
2021-11-15 8:02 ` [PATCH v6 16/23] mm/hugetlb: Allow uffd wr-protect none ptes Peter Xu
2021-11-15 8:02 ` [PATCH v6 17/23] mm/hugetlb: Only drop uffd-wp special pte if required Peter Xu
2021-11-15 8:02 ` [PATCH v6 18/23] mm/hugetlb: Handle uffd-wp during fork() Peter Xu
2021-11-15 8:03 ` [PATCH v6 19/23] mm/khugepaged: Don't recycle vma pgtable if uffd-wp registered Peter Xu
2021-11-15 8:03 ` [PATCH v6 20/23] mm/pagemap: Recognize uffd-wp bit for shmem/hugetlbfs Peter Xu
2021-11-15 8:03 ` [PATCH v6 21/23] mm/uffd: Enable write protection for shmem & hugetlbfs Peter Xu
2021-11-15 8:03 ` [PATCH v6 22/23] mm: Enable PTE markers by default Peter Xu
2021-11-15 8:04 ` [PATCH v6 23/23] selftests/uffd: Enable uffd-wp for shmem/hugetlbfs Peter Xu
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