The patch titled
mremap: check for overflow using deltas
has been added to the -mm tree. Its filename is
mremap-check-for-overflow-using-deltas.patch
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------------------------------------------------------
Subject: mremap: check for overflow using deltas
From: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Using "- 1" relies on the old_end to be page aligned and PAGE_SIZE > 1,
those are reasonable requirements but the check remains obscure and it
looks more like an off by one error than an overflow check. This I feel
will improve readability.
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Acked-by: Johannes Weiner <jweiner@xxxxxxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mremap.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff -puN mm/mremap.c~mremap-check-for-overflow-using-deltas mm/mremap.c
--- a/mm/mremap.c~mremap-check-for-overflow-using-deltas
+++ a/mm/mremap.c
@@ -141,9 +141,10 @@ unsigned long move_page_tables(struct vm
for (; old_addr < old_end; old_addr += extent, new_addr += extent) {
cond_resched();
next = (old_addr + PMD_SIZE) & PMD_MASK;
- if (next - 1 > old_end)
- next = old_end;
+ /* even if next overflowed, extent below will be ok */
extent = next - old_addr;
+ if (extent > old_end - old_addr)
+ extent = old_end - old_addr;
old_pmd = get_old_pmd(vma->vm_mm, old_addr);
if (!old_pmd)
continue;
_
Patches currently in -mm which might be from aarcange@xxxxxxxxxx are
mm-compaction-trivial-clean-up-in-acct_isolated.patch
mm-change-isolate-mode-from-define-to-bitwise-type.patch
mm-compaction-make-isolate_lru_page-filter-aware.patch
mm-zone_reclaim-make-isolate_lru_page-filter-aware.patch
mm-migration-clean-up-unmap_and_move.patch
mremap-check-for-overflow-using-deltas.patch
mremap-avoid-sending-one-ipi-per-page.patch
thp-mremap-support-and-tlb-optimization.patch
thp-mremap-support-and-tlb-optimization-fix.patch
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