Commit 69a8ec2d authored Feb 17, 2016 by Kirill A. Shutemov Committed by Linus Torvalds Feb 18, 2016

thp, dax: do not try to withdraw pgtable from non-anon VMA

DAX doesn't deposit pgtables when it maps huge pages: nothing to
withdraw. It can lead to crash.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 65c23c65

mm/huge_memory.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1700,7 +1700,8 @@ bool move_huge_pmd(struct vm_area_struct vma, struct vm_area_struct new_vma,
		pmd = pmdp_huge_get_and_clear(mm, old_addr, old_pmd);
		VM_BUG_ON(!pmd_none(*new_pmd));

		if (pmd_move_must_withdraw(new_ptl, old_ptl)) {
		if (pmd_move_must_withdraw(new_ptl, old_ptl) &&
		vma_is_anonymous(vma)) {
		pgtable_t pgtable;
		pgtable = pgtable_trans_huge_withdraw(mm, old_pmd);
		pgtable_trans_huge_deposit(mm, new_pmd, pgtable);