From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2BDBFC43387 for ; Wed, 9 Jan 2019 02:02:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 064AE206BB for ; Wed, 9 Jan 2019 02:02:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729516AbfAICCJ (ORCPT ); Tue, 8 Jan 2019 21:02:09 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48462 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728593AbfAICCI (ORCPT ); Tue, 8 Jan 2019 21:02:08 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BE410C0669AB; Wed, 9 Jan 2019 02:02:08 +0000 (UTC) Received: from sky.random (ovpn-120-73.rdu2.redhat.com [10.10.120.73]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AC71B5C57B; Wed, 9 Jan 2019 02:02:05 +0000 (UTC) From: Andrea Arcangeli To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Mike Rapoport , Mike Kravetz , Peter Xu , "Dr. David Alan Gilbert" Subject: [PATCH 0/1] mm/hugetlb.c: teach follow_hugetlb_page() to handle FOLL_NOWAIT Date: Tue, 8 Jan 2019 21:02:02 -0500 Message-Id: <20190109020203.26669-1-aarcange@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Wed, 09 Jan 2019 02:02:08 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, this fixes a regression that resurfaced in hugetlbfs code after we fixed it for the core VM a few months ago. This is only reproducible doing postcopy live migration of KVM (the only user of FOLL_NOWAIT) if backed by hugetlbfs memory. It's unrelated to userfaultfd, but userfaultfd reproduces it easily because it's an heavy user of VM_FAULT_RETRY retvals. Thanks, Andrea Andrea Arcangeli (1): mm/hugetlb.c: teach follow_hugetlb_page() to handle FOLL_NOWAIT mm/hugetlb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)