Commit b1783bf8 authored Jun 24, 2021 by Hugh Dickins Committed by Sasha Levin Jun 30, 2021

mm: page_vma_mapped_walk(): crossing page table boundary

page_vma_mapped_walk() cleanup: adjust the test for crossing page table
boundary - I believe pvmw->address is always page-aligned, but nothing
else here assumed that; and remember to reset pvmw->pte to NULL after
unmapping the page table, though I never saw any bug from that.

Link: https://lkml.kernel.org/r/799b3f9c-2a9e-dfef-5d89-26e9f76fd97@google.com


Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 80b2270a

mm/page_vma_mapped.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -239,16 +239,16 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
		if (pvmw->address >= end)
		return not_found(pvmw);
		/* Did we cross page table boundary? */
		if (pvmw->address % PMD_SIZE == 0) {
		pte_unmap(pvmw->pte);
		if ((pvmw->address & (PMD_SIZE - PAGE_SIZE)) == 0) {
		if (pvmw->ptl) {
		spin_unlock(pvmw->ptl);
		pvmw->ptl = NULL;
		}
		pte_unmap(pvmw->pte);
		pvmw->pte = NULL;
		goto restart;
		} else {
		pvmw->pte++;
		}
		pvmw->pte++;
		} while (pte_none(*pvmw->pte));

		if (!pvmw->ptl) {