From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753674Ab2KVSdy (ORCPT ); Thu, 22 Nov 2012 13:33:54 -0500 Received: from mail.kernel.org ([198.145.19.201]:49018 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753581Ab2KVSdo (ORCPT ); Thu, 22 Nov 2012 13:33:44 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Takamori Yamaguchi , Aaditya Kumar , David Rientjes , Andrew Morton , Linus Torvalds Subject: [ 001/171] mm: bugfix: set current->reclaim_state to NULL while returning from kswapd() Date: Wed, 21 Nov 2012 16:39:07 -0800 Message-Id: <20121122004033.448313282@linuxfoundation.org> X-Mailer: git-send-email 1.8.0.197.g5a90748 In-Reply-To: <20121122004033.298367941@linuxfoundation.org> References: <20121122004033.298367941@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ 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 --- mm/vmscan.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3128,6 +3128,8 @@ static int kswapd(void *p) &balanced_classzone_idx); } } + + current->reclaim_state = NULL; return 0; }