qubes-linux-kernel/patches.suse/SoN-31-fix-null-pointer-dereference

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2011-04-19 20:09:59 +00:00
From: Xiaotian Feng <dfeng@redhat.com>
Subject: fix null pointer deref in swap_entry_free
Patch-mainline: Not yet
Commit b3a27d uses p->bdev->bd_disk, this will lead a null pointer
deref with swap over nfs.
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
--
Index: linux-2.6.35-master/mm/swapfile.c
===================================================================
--- linux-2.6.35-master.orig/mm/swapfile.c
+++ linux-2.6.35-master/mm/swapfile.c
@@ -574,7 +574,6 @@ static unsigned char swap_entry_free(str
/* free if no reference */
if (!usage) {
- struct gendisk *disk = p->bdev->bd_disk;
if (offset < p->lowest_bit)
p->lowest_bit = offset;
if (offset > p->highest_bit)
@@ -584,9 +583,11 @@ static unsigned char swap_entry_free(str
swap_list.next = p->type;
nr_swap_pages++;
p->inuse_pages--;
- if ((p->flags & SWP_BLKDEV) &&
- disk->fops->swap_slot_free_notify)
- disk->fops->swap_slot_free_notify(p->bdev, offset);
+ if (p->flags & SWP_BLKDEV) {
+ struct gendisk *disk = p->bdev->bd_disk;
+ if (disk->fops->swap_slot_free_notify)
+ disk->fops->swap_slot_free_notify(p->bdev, offset);
+ }
}
return usage;