From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754384AbcDDMgk (ORCPT ); Mon, 4 Apr 2016 08:36:40 -0400 Received: from mx2.suse.de ([195.135.220.15]:43494 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751968AbcDDMgi (ORCPT ); Mon, 4 Apr 2016 08:36:38 -0400 Subject: Re: [PATCH] mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check To: Konstantin Khlebnikov , linux-mm@kvack.org, Andrew Morton References: <145961146490.28194.16019687861681349309.stgit@zurg> Cc: Dmitry Vyukov , Andrea Arcangeli , linux-kernel@vger.kernel.org, stable From: Vlastimil Babka Message-ID: <57025FD3.4060004@suse.cz> Date: Mon, 4 Apr 2016 14:36:35 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.0 MIME-Version: 1.0 In-Reply-To: <145961146490.28194.16019687861681349309.stgit@zurg> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/02/2016 05:37 PM, Konstantin Khlebnikov wrote: > Khugepaged detects own VMAs by checking vm_file and vm_ops but this > way it cannot distinguish private /dev/zero mappings from other special > mappings like /dev/hpet which has no vm_ops and popultes PTEs in mmap. > > This fixes false-positive VM_BUG_ON and prevents installing THP where > they are not expected. > > Signed-off-by: Konstantin Khlebnikov > Reported-by: Dmitry Vyukov > Link: http://lkml.kernel.org/r/CACT4Y+ZmuZMV5CjSFOeXviwQdABAgT7T+StKfTqan9YDtgEi5g@mail.gmail.com > Fixes: 78f11a255749 ("mm: thp: fix /dev/zero MAP_PRIVATE and vm_flags cleanups") > Cc: stable Acked-by: Vlastimil Babka