Commit e20d103b authored Oct 13, 2017 by Mark Hairgrove Committed by Linus Torvalds Oct 13, 2017

mm/migrate: fix indexing bug (off by one) and avoid out of bound access

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: 8315ada7 ("mm/migrate: allow migrate_vma() to alloc new page on empty entry")
Signed-off-by: Mark Hairgrove <mhairgrove@nvidia.com>
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Reza Arbab <arbab@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 997301a8

mm/migrate.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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++;
		}