From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oa0-f43.google.com (mail-oa0-f43.google.com [209.85.219.43]) by kanga.kvack.org (Postfix) with ESMTP id 8D8926B0035 for ; Mon, 28 Apr 2014 18:39:17 -0400 (EDT) Received: by mail-oa0-f43.google.com with SMTP id eb12so8040175oac.2 for ; Mon, 28 Apr 2014 15:39:17 -0700 (PDT) Received: from g2t2353.austin.hp.com (g2t2353.austin.hp.com. [15.217.128.52]) by mx.google.com with ESMTPS id rk8si14737282oeb.201.2014.04.28.15.39.16 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 28 Apr 2014 15:39:16 -0700 (PDT) Message-ID: <1398724754.25549.35.camel@buesod1.americas.hpqcorp.net> Subject: Re: [BUG] kernel BUG at mm/vmacache.c:85! From: Davidlohr Bueso 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" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: 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 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, 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