Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755325AbaD1WjS (ORCPT ); Mon, 28 Apr 2014 18:39:18 -0400 Received: from g2t2353.austin.hp.com ([15.217.128.52]:53821 "EHLO g2t2353.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752586AbaD1WjR (ORCPT ); Mon, 28 Apr 2014 18:39:17 -0400 Message-ID: <1398724754.25549.35.camel@buesod1.americas.hpqcorp.net> Subject: Re: [BUG] kernel BUG at mm/vmacache.c:85! From: Davidlohr Bueso To: Linus Torvalds Cc: "Srivatsa S. Bhat" , Linux MM , "linux-kernel@vger.kernel.org" , Rik van Riel , Michel Lespinasse , Hugh Dickins , "akpm@linux-foundation.org" , Oleg Nesterov Date: Mon, 28 Apr 2014 15:39:14 -0700 In-Reply-To: References: <535EA976.1080402@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.4 (3.6.4-3.fc18) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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(). -- 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/