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authorHugh Dickins <hughd@google.com>2021-06-24 18:39:14 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-06-24 19:40:53 -0700
commit448282487483d6fa5b2eeeafaa0acc681e544a9c (patch)
tree23097bf7a0c1de1b5ce8e8035cf11365e78d32c5
parente2e1d4076c77b3671cf8ce702535ae7dee3acf89 (diff)
downloadlinux-448282487483d6fa5b2eeeafaa0acc681e544a9c.tar.gz
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>
-rw-r--r--mm/page_vma_mapped.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index 261fc929b08d..9c87b3090a1b 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -244,16 +244,16 @@ next_pte:
 			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) {