From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx118.postini.com [74.125.245.118]) by kanga.kvack.org (Postfix) with SMTP id A90FB6B0031 for ; Tue, 30 Jul 2013 19:38:03 -0400 (EDT) Date: Tue, 30 Jul 2013 19:37:23 -0400 From: Dave Jones Subject: Re: [PATCH] hugetlb: fix lockdep splat caused by pmd sharing Message-ID: <20130730233722.GA28747@redhat.com> References: <20130730142957.GG15847@dhcp22.suse.cz> <1375195560-23888-1-git-send-email-mhocko@suse.cz> <20130730145834.GA32226@laptop.programming.kicks-ass.net> <20130730152333.GJ15847@dhcp22.suse.cz> <20130730233530.GA19340@bbox> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130730233530.GA19340@bbox> Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Michal Hocko , Peter Zijlstra , Andrew Morton , "Aneesh Kumar K.V" , Rik van Riel , KAMEZAWA Hiroyuki , Hillf Danton , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Wed, Jul 31, 2013 at 08:35:30AM +0900, Minchan Kim wrote: > > which is a false positive caused by hugetlb pmd sharing code which > > allocates a new pmd from withing mappint->i_mmap_mutex. If this > > allocation causes reclaim then the lockdep detector complains that we > > might self-deadlock. > > > > This is not correct though, because hugetlb pages are not reclaimable so > > their mapping will be never touched from the reclaim path. > > > > The patch tells lockup detector that hugetlb i_mmap_mutex is special > > by assigning it a separate lockdep class so it won't report possible > > deadlocks on unrelated mappings. > > > > [peterz@infradead.org: comment for annotation] > > Reported-by: Dave Jones > > Signed-off-by: Michal Hocko > Reviewed-by: Minchan Kim > > Thanks, Michal! > Only remained thing is Dave's testing. I've added it to my builds, all is quiet so far.. Dave -- 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