From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753631Ab1HVTt4 (ORCPT ); Mon, 22 Aug 2011 15:49:56 -0400 Received: from e33.co.us.ibm.com ([32.97.110.151]:57665 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753602Ab1HVTtw (ORCPT ); Mon, 22 Aug 2011 15:49:52 -0400 Message-ID: <4E52B2D9.5070904@linux.vnet.ibm.com> Date: Mon, 22 Aug 2011 14:49:45 -0500 From: Seth Jennings User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.18) Gecko/20110617 Thunderbird/3.1.11 MIME-Version: 1.0 To: Dan Carpenter CC: gregkh@suse.de, devel@driverdev.osuosl.org, dan.magenheimer@oracle.com, ascardo@holoscopio.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] staging: zcache: fix possible sleep under lock References: <1314038869-8164-1-git-send-email-sjenning@linux.vnet.ibm.com> <20110822190936.GA12248@shale.localdomain> In-Reply-To: <20110822190936.GA12248@shale.localdomain> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/22/2011 02:09 PM, Dan Carpenter wrote: > On Mon, Aug 22, 2011 at 01:47:49PM -0500, Seth Jennings wrote: >> zcache_new_pool() calls kmalloc() with GFP_KERNEL which has >> __GFP_WAIT set. However, zcache_new_pool() gets called on >> a stack that holds the swap_lock spinlock, leading to a >> possible sleep-with-lock situation. The lock is obtained >> in enable_swap_info(). >> >> The patch replaces GFP_KERNEL with GFP_IOFS, which is >> GFP_KERNEL & ~__GFP_WAIT. >> > > You should use GFP_ATOMIC. We don't want to do IO with the locks > held. The only reason GFP_IOFS exists is so that we can turn off > io during suspend and resume. > > regards, > dan carpenter > Actually, should this be GFP_ATOMIC or GFP_NOWAIT? -- Seth