The quilt patch titled
Subject: mm/hugetlb: make follow_hugetlb_page() safe to pmd unshare
has been removed from the -mm tree. Its filename was
mm-hugetlb-make-follow_hugetlb_page-safe-to-pmd-unshare.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Peter Xu <peterx@xxxxxxxxxx>
Subject: mm/hugetlb: make follow_hugetlb_page() safe to pmd unshare
Date: Fri, 16 Dec 2022 10:52:23 -0500
Since follow_hugetlb_page() walks the pgtable, it needs the vma lock to
make sure the pgtable page will not be freed concurrently.
Link: https://lkml.kernel.org/r/20221216155223.2043727-1-peterx@xxxxxxxxxx
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: James Houghton <jthoughton@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Nadav Amit <nadav.amit@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/mm/hugetlb.c~mm-hugetlb-make-follow_hugetlb_page-safe-to-pmd-unshare
+++ a/mm/hugetlb.c
@@ -6454,6 +6454,7 @@ long follow_hugetlb_page(struct mm_struc
break;
}
+ hugetlb_vma_lock_read(vma);
/*
* Some archs (sparc64, sh*) have multiple pte_ts to
* each hugepage. We have to make sure we get the
@@ -6478,6 +6479,7 @@ long follow_hugetlb_page(struct mm_struc
!hugetlbfs_pagecache_present(h, vma, vaddr)) {
if (pte)
spin_unlock(ptl);
+ hugetlb_vma_unlock_read(vma);
remainder = 0;
break;
}
@@ -6499,6 +6501,8 @@ long follow_hugetlb_page(struct mm_struc
if (pte)
spin_unlock(ptl);
+ hugetlb_vma_unlock_read(vma);
+
if (flags & FOLL_WRITE)
fault_flags |= FAULT_FLAG_WRITE;
else if (unshare)
@@ -6561,6 +6565,7 @@ long follow_hugetlb_page(struct mm_struc
remainder -= pages_per_huge_page(h);
i += pages_per_huge_page(h);
spin_unlock(ptl);
+ hugetlb_vma_unlock_read(vma);
continue;
}
@@ -6590,6 +6595,7 @@ long follow_hugetlb_page(struct mm_struc
if (WARN_ON_ONCE(!try_grab_folio(pages[i], refs,
flags))) {
spin_unlock(ptl);
+ hugetlb_vma_unlock_read(vma);
remainder = 0;
err = -ENOMEM;
break;
@@ -6601,6 +6607,7 @@ long follow_hugetlb_page(struct mm_struc
i += refs;
spin_unlock(ptl);
+ hugetlb_vma_unlock_read(vma);
}
*nr_pages = remainder;
/*
_
Patches currently in -mm which might be from peterx@xxxxxxxxxx are
selftests-vm-remove-__use_gnu-in-hugetlb-madvisec.patch
