hwpoison: fix oops on ksm pages
Memory failure on a KSM page currently oopses on its NULL anon_vma in
page_lock_anon_vma(): that may not be much worse than the consequence of
ignoring it, but it is better to be consistent with how ZERO_PAGE and
hugetlb pages and other awkward cases are treated. Just skip it.
We could fix it for 2.6.32 at the KSM end, by putting a dummy anon_vma
pointer in there; but that would get harder next time, when KSM will put a
pointer to something else there (and I'm not currently planning to do any
work to open that up to memory_failure). So I would prefer this simple
PageKsm test, until the other exceptions are handled.
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 729d4b1..7fc2130 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -35,6 +35,7 @@
#include <linux/mm.h>
#include <linux/page-flags.h>
#include <linux/sched.h>
+#include <linux/ksm.h>
#include <linux/rmap.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
@@ -661,7 +662,7 @@
int i;
int kill = 1;
- if (PageReserved(p) || PageCompound(p) || PageSlab(p))
+ if (PageReserved(p) || PageCompound(p) || PageSlab(p) || PageKsm(p))
return;
if (!PageLRU(p))