[PATCH 4.19 204/219] staging: comedi: gsc_hpdi: check dma_alloc_coherent() return value

Greg Kroah-Hartman
2019-12-29T17:35:52Z

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
@@ -623,6 +623,11 @@ 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,
@@ -630,6 +635,11 @@ 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");