From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id 6C38F6B01E3 for ; Thu, 22 Apr 2010 15:41:31 -0400 (EDT) Date: Thu, 22 Apr 2010 14:40:46 -0500 (CDT) From: Christoph Lameter Subject: Re: [PATCH 04/14] mm,migration: Allow the migration of PageSwapCache pages In-Reply-To: <20100422192923.GH30306@csn.ul.ie> Message-ID: References: <20100421153421.GM30306@csn.ul.ie> <20100422092819.GR30306@csn.ul.ie> <20100422184621.0aaaeb5f.kamezawa.hiroyu@jp.fujitsu.com> <20100422193106.9ffad4ec.kamezawa.hiroyu@jp.fujitsu.com> <20100422195153.d91c1c9e.kamezawa.hiroyu@jp.fujitsu.com> <20100422141404.GA30306@csn.ul.ie> <20100422154003.GC30306@csn.ul.ie> <20100422192923.GH30306@csn.ul.ie> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: Minchan Kim , KAMEZAWA Hiroyuki , Andrew Morton , Andrea Arcangeli , Adam Litke , Avi Kivity , David Rientjes , KOSAKI Motohiro , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Thu, 22 Apr 2010, Mel Gorman wrote: > vma_adjust() is updating anon VMA information without any locks taken. > In constract, file-backed mappings use the i_mmap_lock. This lack of > locking can result in races with page migration. During rmap_walk(), > vma_address() can return -EFAULT for an address that will soon be valid. > This leaves a dangling migration PTE behind which can later cause a > BUG_ON to trigger when the page is faulted in. Isnt this also a race with reclaim / swap? -- 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