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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 45044C3A589 for ; Tue, 20 Aug 2019 16:00:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1069822CF7 for ; Tue, 20 Aug 2019 16:00:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1069822CF7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A02676B0006; Tue, 20 Aug 2019 12:00:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9B30C6B0007; Tue, 20 Aug 2019 12:00:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8C93B6B0008; Tue, 20 Aug 2019 12:00:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0064.hostedemail.com [216.40.44.64]) by kanga.kvack.org (Postfix) with ESMTP id 67D276B0006 for ; Tue, 20 Aug 2019 12:00:03 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 0E015181AC9CC for ; Tue, 20 Aug 2019 16:00:03 +0000 (UTC) X-FDA: 75843267486.08.wax61_74b1f906f1d59 X-HE-Tag: wax61_74b1f906f1d59 X-Filterd-Recvd-Size: 2489 Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by imf07.hostedemail.com (Postfix) with ESMTP for ; Tue, 20 Aug 2019 16:00:01 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 82EB518C8901; Tue, 20 Aug 2019 15:59:56 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (ovpn-204-99.brq.redhat.com [10.40.204.99]) by smtp.corp.redhat.com (Postfix) with SMTP id 8A16F5DC1B; Tue, 20 Aug 2019 15:59:50 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Tue, 20 Aug 2019 17:59:56 +0200 (CEST) Date: Tue, 20 Aug 2019 17:59:49 +0200 From: Oleg Nesterov To: Andrea Arcangeli Cc: Kefeng Wang , Michal Hocko , linux-mm , Peter Xu , Mike Rapoport , Jann Horn , Jason Gunthorpe , Andrew Morton Subject: Re: [BUG] kernel BUG at fs/userfaultfd.c:385 after 04f5866e41fb Message-ID: <20190820155948.GA4983@redhat.com> References: <20190814135351.GY17933@dhcp22.suse.cz> <7e0e4254-17f4-5f07-e9af-097c4162041a@huawei.com> <20190814151049.GD11595@redhat.com> <20190814154101.GF11595@redhat.com> <20190819160517.GG31518@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190819160517.GG31518@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.70]); Tue, 20 Aug 2019 16:00:00 +0000 (UTC) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 08/19, Andrea Arcangeli wrote: > > The proposed fix looks correct, can you resend in a way that can be merged? OK, I'll send the same patch to lkml, the only change is s/xxx/still_valid/. > It's a bit strange that the file that > was opened by the ioctl() syscall gets released and this look like another bug we need to investigate, > Anyway the same race condition can still happen for a rogue page fault > that is happening when the core dump start so the above fix is needed > anyway. Yes. Oleg.