[PATCH 5.3 082/148] xen/balloon: Set pages PageOffline() in balloon_add_region()

From: Greg Kroah-Hartman
Date: Thu Oct 10 2019 - 04:42:27 EST

From: David Hildenbrand <david@xxxxxxxxxx>

commit c5ad81eb029570c5ca5859539b0679f07a776d25 upstream.

We are missing a __SetPageOffline(), which is why we can get
!PageOffline() pages onto the balloon list, where
alloc_xenballooned_pages() will complain:

page:ffffea0003e7ffc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xffffe00001000(reserved)
raw: 000ffffe00001000 dead000000000100 dead000000000200 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: VM_BUG_ON_PAGE(!PageOffline(page))
------------[ cut here ]------------
kernel BUG at include/linux/page-flags.h:744!
invalid opcode: 0000 [#1] SMP NOPTI

Reported-by: Marek Marczykowski-GÃrecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
Tested-by: Marek Marczykowski-GÃrecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
Fixes: 77c4adf6a6df ("xen/balloon: mark inflated pages PG_offline")
Cc: stable@xxxxxxxxxxxxxxx # v5.1+
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/xen/balloon.c | 1 +
1 file changed, 1 insertion(+)

--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -688,6 +688,7 @@ static void __init balloon_add_region(un
/* totalram_pages and totalhigh_pages do not
include the boot-time balloon extension, so
don't subtract from it. */
+ __SetPageOffline(page);