Commit 92f7ba70 authored Oct 26, 2009 by Hugh Dickins Committed by Linus Torvalds Oct 29, 2009

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>

parent 2eca40a8

mm/memory-failure.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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))

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