From: Peter Xu <peterx@redhat.com>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Andrea Arcangeli <aarcange@redhat.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
David Hildenbrand <david@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Axel Rasmussen <axelrasmussen@google.com>,
Nadav Amit <nadav.amit@gmail.com>
Subject: Re: [PATCH 1/3] mm/hugetlb: Fix race condition of uffd missing/minor handling
Date: Mon, 3 Oct 2022 20:28:03 -0400 [thread overview]
Message-ID: <Yzt+EwJdLr0j9VwH@x1n> (raw)
In-Reply-To: <YztYC+2jalrsxKDm@monkey>
On Mon, Oct 03, 2022 at 02:45:47PM -0700, Mike Kravetz wrote:
> This also explains why the new locking exposes the race.
> hugetlb_change_protection needs to take the i_mmap_sema in write mode because
> it could unshare pmds. Previously, hugetlb page faults took i_mmap_sema in
> read mode so this race could not happen.
Makes sense, thanks for explaining.
--
Peter Xu
next prev parent reply other threads:[~2022-10-04 0:28 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-03 15:56 [PATCH 0/3] mm/hugetlb: Fix selftest failures with write check Peter Xu
2022-10-03 15:56 ` [PATCH 1/3] mm/hugetlb: Fix race condition of uffd missing/minor handling Peter Xu
2022-10-03 17:20 ` Mike Kravetz
2022-10-03 21:27 ` Peter Xu
2022-10-03 21:45 ` Mike Kravetz
2022-10-04 0:28 ` Peter Xu [this message]
2022-10-03 21:00 ` Nadav Amit
2022-10-03 21:16 ` Peter Xu
2022-10-03 21:32 ` Nadav Amit
2022-10-03 15:56 ` [PATCH 2/3] mm/hugetlb: Use hugetlb_pte_stable in migration race check Peter Xu
2022-10-03 15:56 ` [PATCH 3/3] mm/selftest: uffd: Explain the write missing fault check Peter Xu
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