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 Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: ksm: fix losing visibility of part of rmap_item->next list From: Andrea Arcangeli <aarcange@xxxxxxxxxx> 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@xxxxxxxxxx> Cc: Izik Eidus <ieidus@xxxxxxxxxx> Cc: Chris Wright <chrisw@xxxxxxxxxx> Cc: Avi Kivity <avi@xxxxxxxxxx> Cc: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx> Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- 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@xxxxxxxxxx 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 -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html