Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932929AbaD2IDF (ORCPT ); Tue, 29 Apr 2014 04:03:05 -0400 Received: from e28smtp07.in.ibm.com ([122.248.162.7]:48310 "EHLO e28smtp07.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932862AbaD2IC7 (ORCPT ); Tue, 29 Apr 2014 04:02:59 -0400 Message-ID: <535F5C7F.3000608@linux.vnet.ibm.com> Date: Tue, 29 Apr 2014 13:32:07 +0530 From: "Srivatsa S. Bhat" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:15.0) Gecko/20120828 Thunderbird/15.0 MIME-Version: 1.0 To: Davidlohr Bueso CC: Linus Torvalds , Linux MM , "linux-kernel@vger.kernel.org" , Rik van Riel , Michel Lespinasse , Hugh Dickins , "akpm@linux-foundation.org" , Oleg Nesterov Subject: Re: [BUG] kernel BUG at mm/vmacache.c:85! References: <535EA976.1080402@linux.vnet.ibm.com> <1398724754.25549.35.camel@buesod1.americas.hpqcorp.net> In-Reply-To: <1398724754.25549.35.camel@buesod1.americas.hpqcorp.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14042908-8878-0000-0000-00000C2C4E73 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/29/2014 04:09 AM, Davidlohr Bueso wrote: > Adding Oleg. > > On Mon, 2014-04-28 at 14:55 -0700, Linus Torvalds wrote: >> On Mon, Apr 28, 2014 at 2:20 PM, Linus Torvalds >> wrote: >>> >>> That said, the bug does seem to be that some path doesn't invalidate >>> the vmacache sufficiently, or something inserts a vmacache entry into >>> the current process when looking up a remote process or whatever. >>> Davidlohr, ideas? >> >> Maybe we missed some use_mm() call. That will change the current mm >> without flushing the vma cache. The code considers kernel threads to >> be bad targets for vma caching for this reason (and perhaps others), >> but maybe we missed something. >> >> I wonder if we should just invalidate the vma cache in use_mm(), and >> remote the "kernel tasks are special" check. >> >> Srivatsa, are you doing something peculiar on that system that would >> trigger this? I see some kdump failures in the log, anything else? > > Is this perhaps a KVM guest? fwiw I see CONFIG_KVM_ASYNC_PF=y which is a > user of use_mm(). > No, this is just running baremetal on x86. I copied the kernel config of a distro kernel and reused it. Regards, Srivatsa S. Bhat -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/