From e20d103b6c37038ca27409f746f0b3351bcd0c44 Mon Sep 17 00:00:00 2001 From: Mark Hairgrove Date: Fri, 13 Oct 2017 15:57:30 -0700 Subject: [PATCH] mm/migrate: fix indexing bug (off by one) and avoid out of bound access MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Index was incremented before last use and thus the second array could dereference to an invalid address (not mentioning the fact that it did not properly clear the entry we intended to clear). Link: http://lkml.kernel.org/r/1506973525-16491-1-git-send-email-jglisse@redhat.com Fixes: 8315ada7f095bf ("mm/migrate: allow migrate_vma() to alloc new page on empty entry") Signed-off-by: Mark Hairgrove Signed-off-by: Jérôme Glisse Cc: Reza Arbab Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/migrate.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/migrate.c b/mm/migrate.c index 6954c1435833..e00814ca390e 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2146,8 +2146,9 @@ static int migrate_vma_collect_hole(unsigned long start, unsigned long addr; for (addr = start & PAGE_MASK; addr < end; addr += PAGE_SIZE) { - migrate->src[migrate->npages++] = MIGRATE_PFN_MIGRATE; + migrate->src[migrate->npages] = MIGRATE_PFN_MIGRATE; migrate->dst[migrate->npages] = 0; + migrate->npages++; migrate->cpages++; }