From: Bjorn Helgaas <helgaas@kernel.org>
To: Gustavo Pimentel <Gustavo.Pimentel@synopsys.com>
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
dmaengine@vger.kernel.org, "Vinod Koul" <vkoul@kernel.org>,
"Dan Williams" <dan.j.williams@intel.com>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Krzysztof Wilczyński" <kw@linux.com>
Subject: Re: [PATCH v4 15/15] dmaengine: dw-edma: Add pcim_iomap_table return checker
Date: Mon, 8 Feb 2021 13:35:16 -0600 [thread overview]
Message-ID: <20210208193516.GA406304@bjorn-Precision-5520> (raw)
In-Reply-To: <ceb5eb396e417f9e45d39fd5ef565ba77aae6a63.1612389406.git.gustavo.pimentel@synopsys.com>
[+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 <gustavo.pimentel@synopsys.com>
> ---
> 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
>
next prev parent reply other threads:[~2021-02-08 19:37 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-03 21:57 [PATCH v4 00/15] dmaengine: dw-edma: HDMA support Gustavo Pimentel
2021-02-03 21:57 ` [PATCH v4 01/15] dmaengine: dw-edma: Add writeq() and readq() for 64 bits architectures Gustavo Pimentel
2021-02-09 6:29 ` kernel test robot
2021-02-03 21:57 ` [PATCH v4 02/15] dmaengine: dw-edma: Fix comments offset characters' alignment Gustavo Pimentel
2021-02-03 21:57 ` [PATCH v4 03/15] dmaengine: dw-edma: Add support for the HDMA feature Gustavo Pimentel
2021-02-03 21:57 ` [PATCH v4 04/15] PCI: Add pci_find_vsec_capability() to find a specific VSEC Gustavo Pimentel
2021-02-03 21:57 ` [PATCH v4 05/15] dmaengine: dw-edma: Add PCIe VSEC data retrieval support Gustavo Pimentel
2021-02-03 21:57 ` [PATCH v4 06/15] dmaengine: dw-edma: Add device_prep_interleave_dma() support Gustavo Pimentel
2021-02-03 21:57 ` [PATCH v4 07/15] dmaengine: dw-edma: Improve number of channels check Gustavo Pimentel
2021-02-03 21:57 ` [PATCH v4 08/15] dmaengine: dw-edma: Reorder variables to keep consistency Gustavo Pimentel
2021-02-03 21:58 ` [PATCH v4 09/15] dmaengine: dw-edma: Improve the linked list and data blocks definition Gustavo Pimentel
2021-02-03 21:58 ` [PATCH v4 10/15] dmaengine: dw-edma: Change linked list and data blocks offset and sizes Gustavo Pimentel
2021-02-03 21:58 ` [PATCH v4 11/15] dmaengine: dw-edma: Move struct dentry variable from static definition into dw_edma struct Gustavo Pimentel
2021-02-03 21:58 ` [PATCH v4 12/15] dmaengine: dw-edma: Fix crash on loading/unloading driver Gustavo Pimentel
2021-02-03 21:58 ` [PATCH v4 13/15] dmaengine: dw-edma: Change DMA abreviation from lower into upper case Gustavo Pimentel
2021-02-03 21:58 ` [PATCH v4 14/15] dmaengine: dw-edma: Revert fix scatter-gather address calculation Gustavo Pimentel
2021-02-03 21:58 ` [PATCH v4 15/15] dmaengine: dw-edma: Add pcim_iomap_table return checker Gustavo Pimentel
2021-02-08 19:35 ` Bjorn Helgaas [this message]
2021-02-09 15:35 ` Gustavo Pimentel
2021-02-09 18:18 ` Krzysztof Wilczyński
2021-02-09 19:40 ` Krzysztof Wilczyński
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