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>
This commit is contained in:
Hugh Dickins 2009-10-26 16:49:31 -07:00 committed by Linus Torvalds
parent 2eca40a8cc
commit 92f7ba70ee

View file

@ -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 @@ static void hwpoison_user_mappings(struct page *p, unsigned long pfn,
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))