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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 43A4FC433F5 for ; Thu, 30 Aug 2018 14:14:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ECFE62073D for ; Thu, 30 Aug 2018 14:14:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="oTBm6Ljn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ECFE62073D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729283AbeH3SRL (ORCPT ); Thu, 30 Aug 2018 14:17:11 -0400 Received: from mail-pf1-f176.google.com ([209.85.210.176]:45231 "EHLO mail-pf1-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729045AbeH3SRK (ORCPT ); Thu, 30 Aug 2018 14:17:10 -0400 Received: by mail-pf1-f176.google.com with SMTP id i26-v6so3930332pfo.12; Thu, 30 Aug 2018 07:14:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=zurj3wZUUdvWmLzrXQJDu57Ik/qb9GDh/+UW5PIu2QQ=; b=oTBm6Ljn1dFfokD++mhPANd3O6PaHiOTIW4DSVGAx8qrkpvXZX5HtxnDx3TLubV7rZ wqKPuc73wWPtQN6G8SftIWfEss76Hc2T80LmnD9MgNarNTm0+ZvXjrJZbByENpQJurN0 BbUMeRRywA9NhW0NzDkuj850zQx8kdgAZSkmZJZY6aQ6j9xTyh/xdtMaIT3zE8d0TGJe 0soXV5YLUZ1km27qkbqXSjTDarVyBFOJmb1sGPKxAa1e38ya+uyt1eWJHfL22tXfkhip EsrpUwXZQUXTStmQwq9JBiN7WJhiUKKsfIkru6Quw43/cCWwYWvCYhrAOq8R3e15tJGF Z1LQ== 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:content-transfer-encoding :in-reply-to:user-agent; bh=zurj3wZUUdvWmLzrXQJDu57Ik/qb9GDh/+UW5PIu2QQ=; b=ATXaUVF5ACKoUeW1cnrFf6+IpsPv5sZS0DaFV8LTloAt1RgcmMA+VFiegnlOpsrRLG oK1oXNg/hFyhnj1CuPTi2ld0v2s4lcF9YFDhTsAg14o9ynVzov9L9uSzwlbsOGTxRPlP YclOqYWjWMyRzqsn+uDcebEcqfUiOgp03eLIIhvs/4/9hH93oEjSvxfk88wFBBZpDrMh DDfO4so0C68CSvt8jdr+JbkP6NDNyFmwr8ZPpTwsLdHOQ887MtuItPlB6myFRu58FFXu iunDFUkSOleXX7CXQdQq7NBtFS37xv3tY2JyXo2f7ikScW8CDBbLM7mRgTMhaY1bINEm pQEw== X-Gm-Message-State: APzg51D0S91YhTSHJVYGR951TxYnTJ0hS4tdV6BuFG7Zw84hLG8BdHHK sEgNCOZSEgpcDWSK2/pYld4= X-Google-Smtp-Source: ANB0VdYpb3LFKzsQcXlE6p1vRB5GTlbvCQoCYd9YkO4JvLX7jp6i+56Egh3fTHUYWv0eR1Ycv8QuLQ== X-Received: by 2002:aa7:8713:: with SMTP id b19-v6mr10715469pfo.151.1535638489928; Thu, 30 Aug 2018 07:14:49 -0700 (PDT) Received: from localhost (14-202-194-140.static.tpgi.com.au. [14.202.194.140]) by smtp.gmail.com with ESMTPSA id q26-v6sm24972519pfj.127.2018.08.30.07.14.48 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 30 Aug 2018 07:14:49 -0700 (PDT) Date: Fri, 31 Aug 2018 00:14:46 +1000 From: Balbir Singh To: jglisse@redhat.com Cc: linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org, Ralph Campbell , stable@vger.kernel.org Subject: Re: [PATCH 3/7] mm/hmm: fix race between hmm_mirror_unregister() and mmu_notifier callback Message-ID: <20180830141446.GB28695@350D> References: <20180824192549.30844-1-jglisse@redhat.com> <20180824192549.30844-4-jglisse@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20180824192549.30844-4-jglisse@redhat.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 24, 2018 at 03:25:45PM -0400, jglisse@redhat.com wrote: > From: Ralph Campbell > > In hmm_mirror_unregister(), mm->hmm is set to NULL and then > mmu_notifier_unregister_no_release() is called. That creates a small > window where mmu_notifier can call mmu_notifier_ops with mm->hmm equal > to NULL. Fix this by first unregistering mmu notifier callbacks and > then setting mm->hmm to NULL. > > Similarly in hmm_register(), set mm->hmm before registering mmu_notifier > callbacks so callback functions always see mm->hmm set. > > Signed-off-by: Ralph Campbell > Reviewed-by: John Hubbard > Reviewed-by: Jérôme Glisse > Cc: Andrew Morton > Cc: stable@vger.kernel.org Reviewed-by: Balbir Singh