From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752835Ab3FDWmP (ORCPT ); Tue, 4 Jun 2013 18:42:15 -0400 Received: from 1wt.eu ([62.212.114.60]:35384 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752879Ab3FDWmK (ORCPT ); Tue, 4 Jun 2013 18:42:10 -0400 Message-Id: <20130604172131.885884951@1wt.eu> User-Agent: quilt/0.48-1 Date: Tue, 04 Jun 2013 19:22:08 +0200 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Takamori Yamaguchi , Aaditya Kumar , David Rientjes , Andrew Morton , Linus Torvalds , Greg Kroah-Hartman , Willy Tarreau Subject: [ 038/184] mm: bugfix: set current->reclaim_state to NULL while In-Reply-To: <58df134a4b98edf5b0073e2e1e988fe6@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let me know. ------------------ returning from kswapd() From: Takamori Yamaguchi commit b0a8cc58e6b9aaae3045752059e5e6260c0b94bc upstream. In kswapd(), set current->reclaim_state to NULL before returning, as current->reclaim_state holds reference to variable on kswapd()'s stack. In rare cases, while returning from kswapd() during memory offlining, __free_slab() and freepages() can access the dangling pointer of current->reclaim_state. Signed-off-by: Takamori Yamaguchi Signed-off-by: Aaditya Kumar Acked-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman Signed-off-by: Willy Tarreau --- mm/vmscan.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/vmscan.c b/mm/vmscan.c index 4649929..738db2b 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2241,6 +2241,8 @@ static int kswapd(void *p) balance_pgdat(pgdat, order); } } + + current->reclaim_state = NULL; return 0; } -- 1.7.12.2.21.g234cd45.dirty