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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 E7881C7618F for ; Mon, 22 Jul 2019 18:45:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B666721955 for ; Mon, 22 Jul 2019 18:45:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730264AbfGVSp0 (ORCPT ); Mon, 22 Jul 2019 14:45:26 -0400 Received: from mail-vs1-f68.google.com ([209.85.217.68]:36211 "EHLO mail-vs1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727891AbfGVSp0 (ORCPT ); Mon, 22 Jul 2019 14:45:26 -0400 Received: by mail-vs1-f68.google.com with SMTP id y16so26937754vsc.3 for ; Mon, 22 Jul 2019 11:45:25 -0700 (PDT) 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; bh=0oC255nlMTJCbfZqi2fsaWmaMOyLtXK3narxYZHsJ+g=; b=b6FASxVeA9Kh4XenvxeD561sYuDNRW8lxMcV15TzZBtSuozaO9vnzUdysy5eU4f5/d yAp1HL7i3iQ/BDcOgDuSVHalE9j+TPOCIu/9EU/2KfisOhINKO3FQmmLl35HC71tvBM+ csyZBad86KZ60ugn6pTazPfyavGy9HATVdTwQbazUG+TtrUk3B5Df+bHXHdE3GZUTHN/ DF7d8ssIQix9IHtvvLE8tl/59KSgQe8+PXI7YfqJtPA747ZR9rBRGVuyJlNYf5n2pnY7 mqVjXc8zqMsZIF+uzbW2yX8oP5jbRg58o2+d+gF+URON8FeND9TrLEoNmfiCzvavHYK0 zNpg== X-Gm-Message-State: APjAAAVlNEBW14yqjdkRNc2RR/xXY4Vn8FbAPgAEuro04YlnSkufEv1h UMsPHKMdIuVTnon6vhWJ4DzcKg== X-Google-Smtp-Source: APXvYqy1dMOsoJwK19xN4gvienu0+UYNi8SU4/cq7VQCMGv+XWMnqskbibzUi+xg/xwOJYk7B7n4Xw== X-Received: by 2002:a67:7a11:: with SMTP id v17mr45678796vsc.114.1563821125566; Mon, 22 Jul 2019 11:45:25 -0700 (PDT) Received: from redhat.com (bzq-79-181-91-42.red.bezeqint.net. [79.181.91.42]) by smtp.gmail.com with ESMTPSA id u8sm15327600vke.34.2019.07.22.11.45.21 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 22 Jul 2019 11:45:24 -0700 (PDT) Date: Mon, 22 Jul 2019 14:45:18 -0400 From: "Michael S. Tsirkin" To: Eric Auger Cc: eric.auger.pro@gmail.com, hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com, jasowang@redhat.com, virtualization@lists.linux-foundation.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] dma-mapping: Use dma_get_mask in dma_addressing_limited Message-ID: <20190722143724-mutt-send-email-mst@kernel.org> References: <20190722165149.3763-1-eric.auger@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190722165149.3763-1-eric.auger@redhat.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jul 22, 2019 at 06:51:49PM +0200, Eric Auger wrote: > We currently have cases where the dma_addressing_limited() gets > called with dma_mask unset. This causes a NULL pointer dereference. > > Use dma_get_mask() accessor to prevent the crash. > > Fixes: b866455423e0 ("dma-mapping: add a dma_addressing_limited helper") > Signed-off-by: Eric Auger Acked-by: Michael S. Tsirkin If possible I really prefer this approach: avoids changing all callers and uses documented interfaces. > --- > > v1 -> v2: > - was [PATCH 1/2] dma-mapping: Protect dma_addressing_limited > against NULL dma_mask > - Use dma_get_mask > --- > include/linux/dma-mapping.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h > index e11b115dd0e4..f7d1eea32c78 100644 > --- a/include/linux/dma-mapping.h > +++ b/include/linux/dma-mapping.h > @@ -689,8 +689,8 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask) > */ > static inline bool dma_addressing_limited(struct device *dev) > { > - return min_not_zero(*dev->dma_mask, dev->bus_dma_mask) < > - dma_get_required_mask(dev); > + return min_not_zero(dma_get_mask(dev), dev->bus_dma_mask) < > + dma_get_required_mask(dev); > } > > #ifdef CONFIG_ARCH_HAS_SETUP_DMA_OPS > -- > 2.20.1