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 A7E11C76190 for ; Mon, 22 Jul 2019 18:57:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6AFD122387 for ; Mon, 22 Jul 2019 18:57:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730857AbfGVS5t (ORCPT ); Mon, 22 Jul 2019 14:57:49 -0400 Received: from mail-vs1-f65.google.com ([209.85.217.65]:42067 "EHLO mail-vs1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732052AbfGVS5L (ORCPT ); Mon, 22 Jul 2019 14:57:11 -0400 Received: by mail-vs1-f65.google.com with SMTP id 190so26989752vsf.9 for ; Mon, 22 Jul 2019 11:57:10 -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=G3LydhjrGZyGaJaE+altqgbzUT7GXQbjY/6XoX/pvZc=; b=Rj0FpiVegyhkEFGvH5FwPsP+HS2oOwKd3h+1as5pPLM1XprqjfBJZax8/KoJAv6NEl ATF9b5ukrKTAShLbuniOdv+bex1gZBZs5vunpMsmJWGm1MtMSEtdCW2Xmuqo/BTzkP0E KeSaLDJayhuO0HqKXiJlVPbr0zXbj7kMddeSDB5eGSAoTwfmzxeoJB2gyYvoHXDAEljT JYpagba4Ge7AzgtT21LwkiwmMmJfoxn3giE3jvKdaGKntkIwWMPfdgo4H5VJ5jwgt+cb rfS0dARCYA1RQcofaWdW1fvgXPcboqkhIA1I4X+2rEJv1bzHo06eiXtc5AX5Y9FDUjuu uEVg== X-Gm-Message-State: APjAAAWcp76wDlr/IR3nxAxV96KMUvGOmn6XLvQykbFgtXRC7JtjLSUb NQxGIzgWokyCS/p5nlCUaWrqzw== X-Google-Smtp-Source: APXvYqzW0y3QVeCN9/3wXCNVqVYfu/ELakwZssJ444dY3sQr1CJFwY193H4yB3WcP4zsonz0yfKcug== X-Received: by 2002:a67:8c84:: with SMTP id o126mr44506592vsd.122.1563821830405; Mon, 22 Jul 2019 11:57:10 -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 l129sm38783525vki.45.2019.07.22.11.57.07 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 22 Jul 2019 11:57:09 -0700 (PDT) Date: Mon, 22 Jul 2019 14:57:04 -0400 From: "Michael S. Tsirkin" To: Auger Eric 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: <20190722145639-mutt-send-email-mst@kernel.org> References: <20190722165149.3763-1-eric.auger@redhat.com> <77ba1061-08b6-421e-a6dd-d5db9851325b@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <77ba1061-08b6-421e-a6dd-d5db9851325b@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 06:56:49PM +0200, Auger Eric wrote: > Hi Christoph, > > On 7/22/19 6:51 PM, 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 > > As a follow-up of my last email, here is a patch featuring > dma_get_mask(). But you don't have the WARN_ON_ONCE anymore, pointing > out suspect users. OTOH these users then simply become okay so no need for WARN_ON_ONCE then :) > Feel free to pick up your preferred approach > > Thanks > > Eric > > > > --- > > > > 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 > >