linux-kernel - [PATCH] hwpoison: fix oops on ksm pages

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <Pine.LNX.4.64.0910131451280.4698@sister.anvils>
Date:	Tue, 13 Oct 2009 15:02:11 +0100 (BST)
From:	Hugh Dickins <hugh.dickins@...cali.co.uk>
To:	Andi Kleen <andi@...stfloor.org>
cc:	Wu Fengguang <fengguang.wu@...el.com>,
	Izik Eidus <ieidus@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] 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.

Signed-off-by: Hugh Dickins <hugh.dickins@...cali.co.uk>
---
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.

 mm/memory-failure.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- 2.6.32-rc4/mm/memory-failure.c	2009-09-28 00:28:41.000000000 +0100
+++ linux/mm/memory-failure.c	2009-10-13 14:09:12.000000000 +0100
@@ -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(struc
 	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))
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/