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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 3399BC35280 for ; Wed, 2 Oct 2019 14:39:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0804421783 for ; Wed, 2 Oct 2019 14:39:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="o22pljnx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726081AbfJBOja (ORCPT ); Wed, 2 Oct 2019 10:39:30 -0400 Received: from mail-qt1-f195.google.com ([209.85.160.195]:33730 "EHLO mail-qt1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726000AbfJBOja (ORCPT ); Wed, 2 Oct 2019 10:39:30 -0400 Received: by mail-qt1-f195.google.com with SMTP id r5so26685762qtd.0 for ; Wed, 02 Oct 2019 07:39:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=7YHqyUZD/8NIZ2SubBXQMgHPSS2u+oGKWBH9fMpoRow=; b=o22pljnxja/9CD7V4C4Qn1J1tj1U0zcwxX6JKuoamq0XxWpooE+3q5sabL2Tr0Xnpi RAgdb9V1d8Cf2nlx9omXQgRqcuUNyi7DSPpzZMqbVl9fQlRChMczEIX4NxHG4pt/ssFj JLXaYAvVeTUVCRvGF1KeZQtcjEHHt0uO8zAnhjWqpFMkihfNgbUFxJsIJQ6qBrjncixs DYMKAdWoT+0iIZcFjysj48v0tGVrwy4B3kkb3xZzU+8AKNS4OvGvNb1QA7Tbj5WB9GAl yZQGxt4uWOHzYgkIJ4x6epYxkOxu1bor7+sG0j/gnqdQMq2b4fPSrDabCOtEPqImqCrt XPhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=7YHqyUZD/8NIZ2SubBXQMgHPSS2u+oGKWBH9fMpoRow=; b=RA1zaxssxWmJOliNei6GKwLcn4HV8BeUyB35Fe5c8Y8mywL8VBvznpWeU2HJTxjHdT /zUF19+mYZ0lB3YaLUYTkO4IgoIlfLgvW0rv/3GWNp+HK0JuT8tixJqLVRjonuGJLYhX WYUZwmgkLGjwGXFeR/z2BtKeppSYRgSifB2JFKepyYyJEumd0fecgdGhkSbc94LLwOUd mBH8UTl2tNY7lkLlFdHUvGOOVR2aEG6ccuEqY/Jx4ak1Hc21ug9jz5fbSAZvgXV8jSiO GVTJH9coYHuiOxtFGJHMLmi/eX6OmTwRNJaQ8kq5XX5BJBVxcH+juk5vEat4DfWTUvlH svKg== X-Gm-Message-State: APjAAAVVPXVsXQ7ItHZ1GLK8RYgM88lortRKWI+C0UwgvF1nRTMuCTTH PZyVTkPR9Gci1shH6k/lpvJLeasnc+E= X-Google-Smtp-Source: APXvYqx2s77HtzscqetmzrgbU5wP2nVoy4k6FeFeTk/+TA557I+ojc6fH4KuDw1QpblX/+ZVpTYMcw== X-Received: by 2002:ac8:3267:: with SMTP id y36mr4360009qta.375.1570027169559; Wed, 02 Oct 2019 07:39:29 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-142-162-113-180.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.162.113.180]) by smtp.gmail.com with ESMTPSA id w9sm2483148qto.44.2019.10.02.07.39.28 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 02 Oct 2019 07:39:28 -0700 (PDT) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1iFfmq-00070n-Hc; Wed, 02 Oct 2019 11:39:28 -0300 Date: Wed, 2 Oct 2019 11:39:28 -0300 From: Jason Gunthorpe To: Leon Romanovsky Cc: linux-rdma@vger.kernel.org, Artemy Kovalyov Subject: Re: [PATCH 2/6] RDMA/mlx5: Fix a race with mlx5_ib_update_xlt on an implicit MR Message-ID: <20191002143928.GE17152@ziepe.ca> References: <20191001153821.23621-1-jgg@ziepe.ca> <20191001153821.23621-3-jgg@ziepe.ca> <20191002081826.GA5855@unreal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191002081826.GA5855@unreal> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Wed, Oct 02, 2019 at 11:18:26AM +0300, Leon Romanovsky wrote: > > @@ -202,15 +225,22 @@ static void mr_leaf_free_action(struct work_struct *work) > > struct ib_umem_odp *odp = container_of(work, struct ib_umem_odp, work); > > int idx = ib_umem_start(odp) >> MLX5_IMR_MTT_SHIFT; > > struct mlx5_ib_mr *mr = odp->private, *imr = mr->parent; > > + struct ib_umem_odp *odp_imr = to_ib_umem_odp(imr->umem); > > + int srcu_key; > > > > mr->parent = NULL; > > synchronize_srcu(&mr->dev->mr_srcu); > > Are you sure that this line is still needed? Yes, in this case the mr->parent is the SRCU 'update' and it blocks seeing this MR in the pagefault handler. It is necessary before calling ib_umem_odp_release below that frees the memory Jason