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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 258D6C43461 for ; Tue, 15 Sep 2020 15:09:41 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 523EF20770 for ; Tue, 15 Sep 2020 15:09:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 523EF20770 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id C82F0863E3; Tue, 15 Sep 2020 15:09:39 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 7G0HlyGljuHL; Tue, 15 Sep 2020 15:09:38 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by fraxinus.osuosl.org (Postfix) with ESMTP id 0EC4F863FF; Tue, 15 Sep 2020 15:09:38 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id EDD66C0864; Tue, 15 Sep 2020 15:09:37 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id E3189C0051 for ; Tue, 15 Sep 2020 15:09:36 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id C5E702052E for ; Tue, 15 Sep 2020 15:09:36 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id MhSiHfsHwHUX for ; Tue, 15 Sep 2020 15:09:34 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by silver.osuosl.org (Postfix) with ESMTPS id 327B0204B0 for ; Tue, 15 Sep 2020 15:09:34 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 8D42568AFE; Tue, 15 Sep 2020 17:09:30 +0200 (CEST) Date: Tue, 15 Sep 2020 17:09:29 +0200 From: Christoph Hellwig To: Thomas Tai Subject: Re: [PATCH] dma-direct: Fix potential NULL pointer dereference Message-ID: <20200915150929.GA19770@lst.de> References: <1600178594-22801-1-git-send-email-thomas.tai@oracle.com> <20200915140719.GA14831@lst.de> <20200915142624.GA16005@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Cc: konrad.wilk@oracle.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, robin.murphy@arm.com, Christoph Hellwig X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Tue, Sep 15, 2020 at 10:40:39AM -0400, Thomas Tai wrote: >> +++ b/include/linux/dma-direct.h >> @@ -62,9 +62,6 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size, >> { >> dma_addr_t end = addr + size - 1; >> - if (!dev->dma_mask) >> - return false; >> - > > I am concerned that some drivers may rely on this NULL checking. Would you > think we can keep this checking and use the following WARN_ON_ONCE()? dma_capable is not a helper for drivers, but just for dma-direct and related code. And this patch adds the checks for the three places how we call into the ->map* methods. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu