The patch titled
rmap: add anon_vma bug checks
has been added to the -mm tree. Its filename is
add-anon_vma-bug-checks.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: rmap: add anon_vma bug checks
From: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Verify the refcounting doesn't go wrong, and resurrect the check in
__page_check_anon_rmap as in old anon-vma code.
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Signed-off-by: Rik van Riel <riel@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/rmap.c | 3 +++
1 file changed, 3 insertions(+)
diff -puN mm/rmap.c~add-anon_vma-bug-checks mm/rmap.c
--- a/mm/rmap.c~add-anon_vma-bug-checks
+++ a/mm/rmap.c
@@ -813,6 +813,7 @@ static void __page_check_anon_rmap(struc
* are initially only visible via the pagetables, and the pte is locked
* over the call to page_add_new_anon_rmap.
*/
+ BUG_ON(page_anon_vma(page)->root != vma->anon_vma->root);
BUG_ON(page->index != linear_page_index(vma, address));
#endif
}
@@ -1416,6 +1417,7 @@ int try_to_munlock(struct page *page)
*/
void drop_anon_vma(struct anon_vma *anon_vma)
{
+ BUG_ON(atomic_read(&anon_vma->external_refcount) <= 0);
if (atomic_dec_and_lock(&anon_vma->external_refcount, &anon_vma->root->lock)) {
struct anon_vma *root = anon_vma->root;
int empty = list_empty(&anon_vma->head);
@@ -1427,6 +1429,7 @@ void drop_anon_vma(struct anon_vma *anon
* the refcount on the root and check if we need to free it.
*/
if (empty && anon_vma != root) {
+ BUG_ON(atomic_read(&root->external_refcount) <= 0);
last_root_user = atomic_dec_and_test(&root->external_refcount);
root_empty = list_empty(&root->head);
}
_
Patches currently in -mm which might be from aarcange@xxxxxxxxxx are
linux-next.patch
hugetlb-call-mmu-notifiers-on-hugepage-cow.patch
define-madv_hugepage.patch
mmap-remove-unnecessary-lock-from-__vma_link.patch
rmap-always-add-new-vmas-at-the-end.patch
ksm-fix-ksm-swapin-time-optimization.patch
rmap-always-use-anon_vma-root-pointer.patch
rmap-resurrect-page_address_in_vma-anon_vma-check.patch
add-anon_vma-bug-checks.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
