From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755463AbbDIOGD (ORCPT ); Thu, 9 Apr 2015 10:06:03 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:47507 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753758AbbDIOGB (ORCPT ); Thu, 9 Apr 2015 10:06:01 -0400 Message-ID: <55268741.8010301@codeaurora.org> Date: Thu, 09 Apr 2015 19:35:53 +0530 From: Susheel Khiani User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130329 Thunderbird/17.0.5 MIME-Version: 1.0 To: akpm@linux-foundation.org, peterz@infradead.org, neilb@suse.de, dhowells@redhat.com, hughd@google.com, paulmcquad@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [Question] ksm: rmap_item pointing to some stale vmas Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, We are seeing an issue during try_to_unmap_ksm where in call to try_to_unmap_one is failing. try_to_unmap_ksm in this particular case is trying to go through vmas associated with each rmap_item->anon_vma. What we see is this that the corresponding page is not mapped to any of the vmas associated with 2 rmap_item. The associated rmap_item in this case looks like pointing to some valid vma but the said page is not found to be mapped under it. try_to_unmap_one thus fails to find valid ptes for these vmas. At the same time we can see that the page actually is mapped in 2 separate and different vmas which are not part of rmap_item associated with page. So whether rmap_item is pointing to some stale vmas and now the mapping has changed? Or there is something else going on here. p Any pointer would be appreciated. -- Susheel Khiani QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation