This is a note to let you know that I've just added the patch titled
mm: don't dereference struct page fields of invalid pages
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-don-t-dereference-struct-page-fields-of-invalid-pages.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Wed Aug 9 11:19:16 PDT 2017
From: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Date: Tue, 10 Jan 2017 16:58:00 -0800
Subject: mm: don't dereference struct page fields of invalid pages
From: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
[ Upstream commit f073bdc51771f5a5c7a8d1191bfc3ae371d44de7 ]
The VM_BUG_ON() check in move_freepages() checks whether the node id of
a page matches the node id of its zone. However, it does this before
having checked whether the struct page pointer refers to a valid struct
page to begin with. This is guaranteed in most cases, but may not be
the case if CONFIG_HOLES_IN_ZONE=y.
So reorder the VM_BUG_ON() with the pfn_valid_within() check.
Link: http://lkml.kernel.org/r/1481706707-6211-2-git-send-email-ard.biesheuvel@xxxxxxxxxx
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
Cc: Yisheng Xie <xieyisheng1@xxxxxxxxxx>
Cc: Robert Richter <rrichter@xxxxxxxxxx>
Cc: James Morse <james.morse@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1527,14 +1527,14 @@ int move_freepages(struct zone *zone,
#endif
for (page = start_page; page <= end_page;) {
- /* Make sure we are not inadvertently changing nodes */
- VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
-
if (!pfn_valid_within(page_to_pfn(page))) {
page++;
continue;
}
+ /* Make sure we are not inadvertently changing nodes */
+ VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
+
if (!PageBuddy(page)) {
page++;
continue;
Patches currently in stable-queue which might be from ard.biesheuvel@xxxxxxxxxx are
queue-4.4/mm-don-t-dereference-struct-page-fields-of-invalid-pages.patch