From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f178.google.com (mail-pd0-f178.google.com [209.85.192.178]) by kanga.kvack.org (Postfix) with ESMTP id 942186B003A for ; Tue, 29 Apr 2014 04:00:40 -0400 (EDT) Received: by mail-pd0-f178.google.com with SMTP id fp1so4520052pdb.23 for ; Tue, 29 Apr 2014 01:00:40 -0700 (PDT) Received: from e28smtp08.in.ibm.com (e28smtp08.in.ibm.com. [122.248.162.8]) by mx.google.com with ESMTPS id hp1si12118801pad.98.2014.04.29.01.00.37 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 29 Apr 2014 01:00:39 -0700 (PDT) Received: from /spool/local by e28smtp08.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 29 Apr 2014 13:30:34 +0530 Received: from d28relay03.in.ibm.com (d28relay03.in.ibm.com [9.184.220.60]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id 0ECC3E0053 for ; Tue, 29 Apr 2014 13:30:50 +0530 (IST) Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s3T80QqZ60948720 for ; Tue, 29 Apr 2014 13:30:26 +0530 Received: from d28av04.in.ibm.com (localhost [127.0.0.1]) by d28av04.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s3T80U9f027235 for ; Tue, 29 Apr 2014 13:30:30 +0530 Message-ID: <535F5BF1.6020405@linux.vnet.ibm.com> Date: Tue, 29 Apr 2014 13:29:45 +0530 From: "Srivatsa S. Bhat" MIME-Version: 1.0 Subject: Re: [BUG] kernel BUG at mm/vmacache.c:85! References: <535EA976.1080402@linux.vnet.ibm.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Linus Torvalds Cc: Linux MM , "linux-kernel@vger.kernel.org" , Davidlohr Bueso , Rik van Riel , Michel Lespinasse , Hugh Dickins , "akpm@linux-foundation.org" On 04/29/2014 03:25 AM, 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? > No, it was just plain booting. The machine is simply configured with kdump, that's all. I'm surprised that so many processes got segfaults during boot. Looks like an mm bug in the kernel. Regards, Srivatsa S. Bhat -- 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