+ ksm-add-replace_page-change-the-page-pte-is-pointing-to-fix-losing-visibility-of-part-of-rmap_item-next-list.patch added to -mm tree

+ ksm-add-replace_page-change-the-page-pte-is-pointing-to-fix-losing-visibility-of-part-of-rmap_item-next-list.patch added to -mm tree

[akpm]

The patch titled
     ksm: fix losing visibility of part of rmap_item->next list
has been added to the -mm tree.  Its filename is
     ksm-add-replace_page-change-the-page-pte-is-pointing-to-fix-losing-visibility-of-part-of-rmap_item-next-list.patch

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------------------------------------------------------
Subject: ksm: fix losing visibility of part of rmap_item->next list
From: Andrea Arcangeli <aarcange@redhat.com>


The tree_item->rmap_item is the head of the list and as such it must
not be overwritten except in the case that the element we removed
(rmap_item) was the previous head of the list, in which case it would
also have rmap_item->prev set to null.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Izik Eidus <ieidus@redhat.com>
Cc: Chris Wright <chrisw@redhat.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/ksm.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff -puN mm/ksm.c~ksm-add-replace_page-change-the-page-pte-is-pointing-to-fix-losing-visibility-of-part-of-rmap_item-next-list mm/ksm.c
--- a/mm/ksm.c~ksm-add-replace_page-change-the-page-pte-is-pointing-to-fix-losing-visibility-of-part-of-rmap_item-next-list
+++ a/mm/ksm.c
@@ -397,10 +397,10 @@ static void remove_rmap_item_from_tree(s
 				free_tree_item(tree_item);
 				nnodes_stable_tree--;
 			} else if (!rmap_item->prev) {
+				BUG_ON(tree_item->rmap_item != rmap_item);
 				tree_item->rmap_item = rmap_item->next;
-			} else {
-				tree_item->rmap_item = rmap_item->prev;
-			}
+			} else
+				BUG_ON(tree_item->rmap_item == rmap_item);
 		} else {
 			/*
 			 * We dont rb_erase(&tree_item->node) here, beacuse
_

Patches currently in -mm which might be from aarcange@redhat.com are

linux-next.patch
ksm-mmu_notifiers-add-set_pte_at_notify.patch
ksm-add-get_pte-helper-function-fetching-pte-for-va.patch
ksm-add-get_pte-helper-function-fetching-pte-for-va-fix.patch
ksm-add-page_wrprotect-write-protecting-page.patch
ksm-add-replace_page-change-the-page-pte-is-pointing-to.patch
ksm-add-ksm-kernel-shared-memory-driver.patch
ksm-add-ksm-kernel-shared-memory-driver-checkpatch-fixes.patch
ksm-add-ksm-kernel-shared-memory-driver-fix-unsafe-pte-fetching.patch
ksm-add-ksm-kernel-shared-memory-driver-limiting-the-num-of-mem-regions-user-can-register-per-fd.patch
ksm-add-ksm-kernel-shared-memory-driver-dont-allow-overlap-memory-addresses-registrations.patch
ksm-add-ksm-kernel-shared-memory-driver-change-the-ksm_remove_memory_region-ioctl.patch
ksm-add-ksm-kernel-shared-memory-driver-change-the-prot-handling-to-use-the-generic-helper-functions.patch
ksm-add-ksm-kernel-shared-memory-driver-use-another-miscdevice-minor-number.patch
ksm-add-ksm-kernel-shared-memory-driver-ksm-fix-rmap_item-use-after-free.patch
ksm-add-replace_page-change-the-page-pte-is-pointing-to-fix-losing-visibility-of-part-of-rmap_item-next-list.patch