The patch titled
Subject: mm/gup: fix __get_user_pages() on fault retry of hugetlb
has been removed from the -mm tree. Its filename was
mm-gup-fix-__get_user_pages-on-fault-retry-of-hugetlb.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Peter Xu <peterx@xxxxxxxxxx>
Subject: mm/gup: fix __get_user_pages() on fault retry of hugetlb
When follow_hugetlb_page() returns with *locked==0, it means we've got a
VM_FAULT_RETRY within the fauling process and we've released the mmap_sem.
When that happens, we should stop and bail out.
Link: http://lkml.kernel.org/r/20200220155353.8676-3-peterx@xxxxxxxxxx
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
Tested-by: Brian Geffon <bgeffon@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Bobby Powers <bobbypowers@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Denis Plotnikov <dplotnikov@xxxxxxxxxxxxx>
Cc: "Dr . David Alan Gilbert" <dgilbert@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: "Kirill A . Shutemov" <kirill@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Martin Cracauer <cracauer@xxxxxxxx>
Cc: Marty McFadden <mcfadden8@xxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Maya Gokhale <gokhale2@xxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/gup.c | 10 ++++++++++
1 file changed, 10 insertions(+)
--- a/mm/gup.c~mm-gup-fix-__get_user_pages-on-fault-retry-of-hugetlb
+++ a/mm/gup.c
@@ -1065,6 +1065,16 @@ static long __get_user_pages(struct task
i = follow_hugetlb_page(mm, vma, pages, vmas,
&start, &nr_pages, i,
gup_flags, locked);
+ if (locked && *locked == 0) {
+ /*
+ * We've got a VM_FAULT_RETRY
+ * and we've lost mmap_sem.
+ * We must stop here.
+ */
+ BUG_ON(gup_flags & FOLL_NOWAIT);
+ BUG_ON(ret != 0);
+ goto out;
+ }
continue;
}
}
_
Patches currently in -mm which might be from peterx@xxxxxxxxxx are
mm-merge-parameters-for-change_protection.patch
userfaultfd-wp-apply-_page_uffd_wp-bit.patch
userfaultfd-wp-drop-_page_uffd_wp-properly-when-fork.patch
userfaultfd-wp-add-pmd_swp_uffd_wp-helpers.patch
userfaultfd-wp-support-swap-and-page-migration.patch
khugepaged-skip-collapse-if-uffd-wp-detected.patch
userfaultfd-wp-dont-wake-up-when-doing-write-protect.patch
userfaultfd-wp-declare-_uffdio_writeprotect-conditionally.patch
userfaultfd-selftests-refactor-statistics.patch
userfaultfd-selftests-add-write-protect-test.patch
