From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: shmem: fix pageflags after swapping DMA32 object
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@xxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [4.8.x]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/shmem.c | 2 ++
1 file changed, 2 insertions(+)
diff -puN mm/shmem.c~shmem-fix-pageflags-after-swapping-dma32-object mm/shmem.c
--- a/mm/shmem.c~shmem-fix-pageflags-after-swapping-dma32-object
+++ a/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);
_
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