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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Ian Abbott <abbotti@mev.co.uk>
Subject: [PATCH 4.9 105/171] staging: comedi: gsc_hpdi: check dma_alloc_coherent() return value
Date:   Thu,  2 Jan 2020 23:07:16 +0100
Message-Id: <20200102220601.724084391@linuxfoundation.org>
In-Reply-To: <20200102220546.960200039@linuxfoundation.org>
References: <20200102220546.960200039@linuxfoundation.org>
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From: Ian Abbott <abbotti@mev.co.uk>

commit ab42b48f32d4c766420c3499ee9c0289b7028182 upstream.

The "auto-attach" handler function `gsc_hpdi_auto_attach()` calls
`dma_alloc_coherent()` in a loop to allocate some DMA data buffers, and
also calls it to allocate a buffer for a DMA descriptor chain.  However,
it does not check the return value of any of these calls.  Change
`gsc_hpdi_auto_attach()` to return `-ENOMEM` if any of these
`dma_alloc_coherent()` calls fail.  This will result in the comedi core
calling the "detach" handler `gsc_hpdi_detach()` as part of the
clean-up, which will call `gsc_hpdi_free_dma()` to free any allocated
DMA coherent memory buffers.

Cc: <stable@vger.kernel.org> #4.6+
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20191216110823.216237-1-abbotti@mev.co.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/staging/comedi/drivers/gsc_hpdi.c |   10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/drivers/staging/comedi/drivers/gsc_hpdi.c
+++ b/drivers/staging/comedi/drivers/gsc_hpdi.c
@@ -632,6 +632,11 @@ static int gsc_hpdi_auto_attach(struct c
 		    dma_alloc_coherent(&pcidev->dev, DMA_BUFFER_SIZE,
 				       &devpriv->dio_buffer_phys_addr[i],
 				       GFP_KERNEL);
+		if (!devpriv->dio_buffer[i]) {
+			dev_warn(dev->class_dev,
+				 "failed to allocate DMA buffer\n");
+			return -ENOMEM;
+		}
 	}
 	/* allocate dma descriptors */
 	devpriv->dma_desc = dma_alloc_coherent(&pcidev->dev,
@@ -639,6 +644,11 @@ static int gsc_hpdi_auto_attach(struct c
 					       NUM_DMA_DESCRIPTORS,
 					       &devpriv->dma_desc_phys_addr,
 					       GFP_KERNEL);
+	if (!devpriv->dma_desc) {
+		dev_warn(dev->class_dev,
+			 "failed to allocate DMA descriptors\n");
+		return -ENOMEM;
+	}
 	if (devpriv->dma_desc_phys_addr & 0xf) {
 		dev_warn(dev->class_dev,
 			 " dma descriptors not quad-word aligned (bug)\n");