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=-9.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 A037CC0650E for ; Mon, 1 Jul 2019 06:21:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5A5A3212F5 for ; Mon, 1 Jul 2019 06:21:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="PSbfEnpL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5A5A3212F5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 16D926B0008; Mon, 1 Jul 2019 02:21:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0EE488E000E; Mon, 1 Jul 2019 02:21:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E0EE08E000D; Mon, 1 Jul 2019 02:21:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-pf1-f205.google.com (mail-pf1-f205.google.com [209.85.210.205]) by kanga.kvack.org (Postfix) with ESMTP id A22616B0008 for ; Mon, 1 Jul 2019 02:21:01 -0400 (EDT) Received: by mail-pf1-f205.google.com with SMTP id x10so8207689pfa.23 for ; Sun, 30 Jun 2019 23:21:01 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:from:to:cc:subject:date :message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=K+5Y7Ez4pfTMCmPiyIGRChGh4O04+aapHsZzDHBkVJo=; b=Fmr/jWQeQ0/sWPa+R2J2tSmybi1SdJqzz4kQ8oqvms5uEfaP95jXkng9Q+Ok2LHbPQ JPRzw/VhLdPLyNPr7O0UPoN6QvdJNpLsWAgFSTnPtWLQov8/d7r6yI9xAzh5UEwGHqZR 7XX7hfozmmOM7nuNVKCDE57PHzuTZytaVu1D0EWxF/7a5W636TJoA7n1W2rXhE/dDgpJ xSJ5AAheRWZauFSMACPGtdvl18gtIr06ZrWUHFZeY3vRH8knAnv6pCzHolxtAtwDCJRH 4dfvLJMLSddjj06njZ6UsvVNg7gtFeu4og2sAUS4RWIkzGZfoqDyqXjiM4MwmSrQLS2P gVMA== X-Gm-Message-State: APjAAAWJn81X6jLgPJehyn/ibpxwSq3Td0KTmpseDXsZTIiezDVBQrdR nZxEmXmHe3gvXhd0qDsh6lCsEIhb3kgXOC4aklEJCHJvCMUzEU0VO9mG+A1y5QN2notj1GXvF1H s7QCSfsIGtNFuoWmmQ/XilBYYjwXwf/oF6mukhWpSN+pzU6tFUYrJmiIhmR3yjOY= X-Received: by 2002:a65:41c5:: with SMTP id b5mr23638728pgq.128.1561962061250; Sun, 30 Jun 2019 23:21:01 -0700 (PDT) X-Google-Smtp-Source: APXvYqwHP95O/rnBry3YUP5e9NvWcg5epvDp5OEf7vpR8kqvVig10c1souAHRZwUMqgEKZ6QTRBr X-Received: by 2002:a65:41c5:: with SMTP id b5mr23638688pgq.128.1561962060488; Sun, 30 Jun 2019 23:21:00 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1561962060; cv=none; d=google.com; s=arc-20160816; b=zj3IrrLFHd40IMDuDP+Dig0NNIZGuxJVjlRX0zLeRJvqqv4jGS5nsb8w8ltPq+lvP6 D+OecISkH7meBxvdobOk+TKbVm965GnTL+ZirV3w93bT3vS26BcXFbkXXkqzSrBianF1 cogPrBthrxxDZ++4cffFaE0UOWbv8Nay4oA/RJgOgr63x+m+EKO1vsOQaUn+FcMKL4Sw 2U9N4GP5Mzqcn/rBduK0+L63mQhVVjPecu8A+JHfbadKwGVTL0V4dTKKn3evEChvTyF0 P40MXKyqbWIMUB5OQWmQqls0eaQdxiaQR0+74vCFrqXJv25QJiFeSuEw4nGaXPWfztZj USLA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:dkim-signature; bh=K+5Y7Ez4pfTMCmPiyIGRChGh4O04+aapHsZzDHBkVJo=; b=Q8rlH5rvxKTyOnPgsFaCtN9DI/0IMdFOB6bkHaPpGKNsuhLunRJZ1MS1zyil8F1Frc Ra5HES97rGCZcGLaJ1Zo99nzID3TqG8EM0g+74nbiK6dnjAifOLWKlhmWFZinYbggxqy mkp2wdBqSnpy4Ie5MGDpHMgyrrsE9Mvsj01iObaBYzx652o+V5uJJXIiHJ1PRy5C2XC7 Z8TWpnDEtYqbZa2U0OMIMl8lkLvvUPlt2HNPoojyFIyA6iYVIb9H9RwFjP15ksIS6xmE fh1LUgnJeCNUpcepkvl4kuqYvrTiu1yBpD+womc53yGb+IglCFvlxnbYuzSC5vINeckQ P1xg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=PSbfEnpL; spf=pass (google.com: best guess record for domain of batv+bb02ddf78a79a38d855c+5790+infradead.org+hch@bombadil.srs.infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=BATV+bb02ddf78a79a38d855c+5790+infradead.org+hch@bombadil.srs.infradead.org Received: from bombadil.infradead.org (bombadil.infradead.org. [2607:7c80:54:e::133]) by mx.google.com with ESMTPS id p97si9685310pjp.34.2019.06.30.23.21.00 for (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Sun, 30 Jun 2019 23:21:00 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of batv+bb02ddf78a79a38d855c+5790+infradead.org+hch@bombadil.srs.infradead.org designates 2607:7c80:54:e::133 as permitted sender) client-ip=2607:7c80:54:e::133; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=PSbfEnpL; spf=pass (google.com: best guess record for domain of batv+bb02ddf78a79a38d855c+5790+infradead.org+hch@bombadil.srs.infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=BATV+bb02ddf78a79a38d855c+5790+infradead.org+hch@bombadil.srs.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc: To:From:Sender:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=K+5Y7Ez4pfTMCmPiyIGRChGh4O04+aapHsZzDHBkVJo=; b=PSbfEnpLRE8SG9bLML+fRlhf0 HtVXUwpI1yGra8E8q+rwV6qJm4ONJSDzOZ753xm3ERQHmxUjdhHbZaiUebewXGu/ryXEdIqi7spGD Nlr6XlnU/i9TC0WMqh3qrx9cT7ITHZkOAeu54JXvWWQ2MaeC+xjlwX/7+GOXnST0/kVvSEpc1HmW/ hO3augHviB0cDdLARWF6uP/j90BGjEpU45QJHn+ssAOFsyOrVWV8bsQFxpmwUu7D3kHoTQPtfD/+9 h1Gpz4y5W71lm5fa5MIvKeZct6x0kCAYyPKLWFw3cLp1onhIVhjCvfTwvaeENThWQJ0FWVoyh0659 oBUZxg5rA==; Received: from [46.140.178.35] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hhpgO-00034k-I0; Mon, 01 Jul 2019 06:20:57 +0000 From: Christoph Hellwig To: Dan Williams , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Jason Gunthorpe , Ben Skeggs Cc: Ira Weiny , linux-mm@kvack.org, nouveau@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-nvdimm@lists.01.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, John Hubbard , Souptick Joarder , Ralph Campbell , Philip Yang Subject: [PATCH 15/22] mm/hmm: Poison hmm_range during unregister Date: Mon, 1 Jul 2019 08:20:13 +0200 Message-Id: <20190701062020.19239-16-hch@lst.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190701062020.19239-1-hch@lst.de> References: <20190701062020.19239-1-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html 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: From: Jason Gunthorpe Trying to misuse a range outside its lifetime is a kernel bug. Use poison bytes to help detect this condition. Double unregister will reliably crash. Signed-off-by: Jason Gunthorpe Reviewed-by: Jérôme Glisse Reviewed-by: John Hubbard Acked-by: Souptick Joarder Reviewed-by: Ralph Campbell Reviewed-by: Ira Weiny Tested-by: Philip Yang --- mm/hmm.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/mm/hmm.c b/mm/hmm.c index 2ef14b2b5505..c30aa9403dbe 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -925,19 +925,21 @@ void hmm_range_unregister(struct hmm_range *range) { struct hmm *hmm = range->hmm; - /* Sanity check this really should not happen. */ - if (hmm == NULL || range->end <= range->start) - return; - mutex_lock(&hmm->lock); list_del_init(&range->list); mutex_unlock(&hmm->lock); /* Drop reference taken by hmm_range_register() */ - range->valid = false; mmput(hmm->mm); hmm_put(hmm); - range->hmm = NULL; + + /* + * The range is now invalid and the ref on the hmm is dropped, so + * poison the pointer. Leave other fields in place, for the caller's + * use. + */ + range->valid = false; + memset(&range->hmm, POISON_INUSE, sizeof(range->hmm)); } EXPORT_SYMBOL(hmm_range_unregister); -- 2.20.1