Patch "shmem: fix pageflags after swapping DMA32 object" has been added to the 4.8-stable tree

This is a note to let you know that I've just added the patch titled

    shmem: fix pageflags after swapping DMA32 object

to the 4.8-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:
     shmem-fix-pageflags-after-swapping-dma32-object.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let [off-list ref] know about it.

From 9956edf37e65e93fbb76dcff1236dff2323d306a Mon Sep 17 00:00:00 2001

From: Hugh Dickins <hughd@google.com>
Date: Thu, 10 Nov 2016 10:46:11 -0800
Subject: shmem: fix pageflags after swapping DMA32 object

From: Hugh Dickins <hughd@google.com>

commit 9956edf37e65e93fbb76dcff1236dff2323d306a upstream.

If shmem_alloc_page() does not set PageLocked and PageSwapBacked, then
shmem_replace_page() needs to do so for itself.  Without this, it puts
newpage on the wrong lru, re-unlocks the unlocked newpage, and system
descends into "Bad page" reports and freeze; or if CONFIG_DEBUG_VM=y, it
hits an earlier VM_BUG_ON_PAGE(!PageLocked), depending on config.

But shmem_replace_page() is not a common path: it's only called when
swapin (or swapoff) finds the page was already read into an unsuitable
zone: usually all zones are suitable, but gem objects for a few drm
devices (gma500, omapdrm, crestline, broadwater) require zone DMA32 if
there's more than 4GB of ram.

Fixes: 800d8c63b2e9 ("shmem: add huge pages support")
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1611062003510.11253@eggly.anvils
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <redacted>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 mm/shmem.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/mm/shmem.c
+++ b/mm/shmem.c

@@ -1483,6 +1483,8 @@ static int shmem_replace_page(struct pag
 	copy_highpage(newpage, oldpage);
 	flush_dcache_page(newpage);
 
+	__SetPageLocked(newpage);
+	__SetPageSwapBacked(newpage);
 	SetPageUptodate(newpage);
 	set_page_private(newpage, swap_index);
 	SetPageSwapCache(newpage);

Patches currently in stable-queue which might be from hughd@google.com are

queue-4.8/swapfile-fix-memory-corruption-via-malformed-swapfile.patch
queue-4.8/shmem-fix-pageflags-after-swapping-dma32-object.patch