From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx185.postini.com [74.125.245.185]) by kanga.kvack.org (Postfix) with SMTP id AB8436B0044 for ; Thu, 23 Aug 2012 16:56:59 -0400 (EDT) Received: by pbbro12 with SMTP id ro12so2364279pbb.14 for ; Thu, 23 Aug 2012 13:56:59 -0700 (PDT) Date: Fri, 24 Aug 2012 05:56:48 +0900 From: Minchan Kim Subject: Re: [PATCH 0/2] revert changes to zcache_do_preload() Message-ID: <20120823205648.GA2066@barrios> References: <1345735991-6995-1-git-send-email-sjenning@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1345735991-6995-1-git-send-email-sjenning@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Seth Jennings Cc: Greg Kroah-Hartman , Andrew Morton , Nitin Gupta , Minchan Kim , Konrad Rzeszutek Wilk , Dan Magenheimer , linux-mm@kvack.org, linux-kernel@vger.kernel.org, devel@driverdev.osuosl.org, xiaoguangrong@linux.vnet.ibm.com Hi Seth, On Thu, Aug 23, 2012 at 10:33:09AM -0500, Seth Jennings wrote: > This patchset fixes a regression in 3.6 by reverting two dependent > commits that made changes to zcache_do_preload(). > > The commits undermine an assumption made by tmem_put() in > the cleancache path that preemption is disabled. This change > introduces a race condition that can result in the wrong page > being returned by tmem_get(), causing assorted errors (segfaults, > apparent file corruption, etc) in userspace. > > The corruption was discussed in this thread: > https://lkml.org/lkml/2012/8/17/494 I think changelog isn't enough to explain what's the race. Could you write it down in detail? And you should Cc'ed Xiao who is author of reverted patch. > > Please apply this patchset to 3.6. This problem didn't exist > in previous releases so nothing need be done for the stable trees. > > Seth Jennings (2): > Revert "staging: zcache: cleanup zcache_do_preload and > zcache_put_page" > Revert "staging: zcache: optimize zcache_do_preload" > > drivers/staging/zcache/zcache-main.c | 54 +++++++++++++++++++--------------- > 1 file changed, 31 insertions(+), 23 deletions(-) > > -- > 1.7.9.5 > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org