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=-16.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 94729C433E0 for ; Mon, 8 Feb 2021 19:37:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 628A664E85 for ; Mon, 8 Feb 2021 19:37:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233655AbhBHTgu (ORCPT ); Mon, 8 Feb 2021 14:36:50 -0500 Received: from mail.kernel.org ([198.145.29.99]:41468 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236348AbhBHTf7 (ORCPT ); Mon, 8 Feb 2021 14:35:59 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7FEE960238; Mon, 8 Feb 2021 19:35:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612812918; bh=MGpnihOYgovKUNDN8RKjHCBSWobXEqBkmqJNNNAU/3k=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=aP+eunnCA20VP1zI4U0hV5jEh6HZTUkp/JehiOF9qu/veMnajkSD5d2+26+ErWDaA Tcnv00QAGC7mX2eSOC4umMTvYmyaUDFSL48/whkYmc/NBMLooV9tSj+40wXUnoj32y Wlw/+DAY9z9B64Sn3MqWj4+z0VkrlGD7rjmso/hy9GIxXxdbO8YB7qqEjNEWZ4I3JG CvCK4/hgZhjsqfI75qq71RnU0UoBgy2UOzmgFT3Jhg7gRP3VvC3GGiPDlgr5KlJ6Us d9JiPxaWK3+709ykTaOxAhQD0CbtxRnKFu2hlsHFyj4CyXnQuLMkl8yhHD9MctBtuC yJPPNzN3u39Ug== Date: Mon, 8 Feb 2021 13:35:16 -0600 From: Bjorn Helgaas To: Gustavo Pimentel Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, Vinod Koul , Dan Williams , Bjorn Helgaas , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= Subject: Re: [PATCH v4 15/15] dmaengine: dw-edma: Add pcim_iomap_table return checker Message-ID: <20210208193516.GA406304@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org [+cc Krzysztof] >From reading the subject, I thought you were adding a function to check the return values, i.e., a "checker." But you're really adding "checks" :) On Wed, Feb 03, 2021 at 10:58:06PM +0100, Gustavo Pimentel wrote: > Detected by CoverityScan CID 16555 ("Dereference null return") > > Signed-off-by: Gustavo Pimentel > --- > drivers/dma/dw-edma/dw-edma-pcie.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/drivers/dma/dw-edma/dw-edma-pcie.c b/drivers/dma/dw-edma/dw-edma-pcie.c > index 686b4ff..7445033 100644 > --- a/drivers/dma/dw-edma/dw-edma-pcie.c > +++ b/drivers/dma/dw-edma/dw-edma-pcie.c > @@ -238,6 +238,9 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev, > dw->rd_ch_cnt = vsec_data.rd_ch_cnt; > > dw->rg_region.vaddr = pcim_iomap_table(pdev)[vsec_data.rg.bar]; > + if (!dw->rg_region.vaddr) > + return -ENOMEM; This doesn't seem quite right. If pcim_iomap_table() fails, it returns NULL. But then we assign "vaddr = NULL[vsec_data.rg.bar]" which dereferences the NULL pointer even before your test. This "pcim_iomap_table(dev)[n]" pattern is extremely common. There are over 100 calls of pcim_iomap_table(), and $ git grep "pcim_iomap_table(.*)\[.*\]" | wc -l says about 75 of them are of this form, where we dereference the result before testing it. > dw->rg_region.vaddr += vsec_data.rg.off; > dw->rg_region.paddr = pdev->resource[vsec_data.rg.bar].start; > dw->rg_region.paddr += vsec_data.rg.off; > @@ -250,12 +253,18 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev, > struct dw_edma_block *dt_block = &vsec_data.dt_wr[i]; > > ll_region->vaddr = pcim_iomap_table(pdev)[ll_block->bar]; > + if (!ll_region->vaddr) > + return -ENOMEM; > + > ll_region->vaddr += ll_block->off; > ll_region->paddr = pdev->resource[ll_block->bar].start; > ll_region->paddr += ll_block->off; > ll_region->sz = ll_block->sz; > > dt_region->vaddr = pcim_iomap_table(pdev)[dt_block->bar]; > + if (!dt_region->vaddr) > + return -ENOMEM; > + > dt_region->vaddr += dt_block->off; > dt_region->paddr = pdev->resource[dt_block->bar].start; > dt_region->paddr += dt_block->off; > @@ -269,12 +278,18 @@ static int dw_edma_pcie_probe(struct pci_dev *pdev, > struct dw_edma_block *dt_block = &vsec_data.dt_rd[i]; > > ll_region->vaddr = pcim_iomap_table(pdev)[ll_block->bar]; > + if (!ll_region->vaddr) > + return -ENOMEM; > + > ll_region->vaddr += ll_block->off; > ll_region->paddr = pdev->resource[ll_block->bar].start; > ll_region->paddr += ll_block->off; > ll_region->sz = ll_block->sz; > > dt_region->vaddr = pcim_iomap_table(pdev)[dt_block->bar]; > + if (!dt_region->vaddr) > + return -ENOMEM; > + > dt_region->vaddr += dt_block->off; > dt_region->paddr = pdev->resource[dt_block->bar].start; > dt_region->paddr += dt_block->off; > -- > 2.7.4 >