This is a note to let you know that I've just added the patch titled

staging: comedi: gsc_hpdi: check dma_alloc_coherent() return value

to my staging git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git in the staging-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From ab42b48f32d4c766420c3499ee9c0289b7028182 Mon Sep 17 00:00:00 2001

From: Ian Abbott abbotti@mev.co.uk Date: Mon, 16 Dec 2019 11:08:23 +0000 Subject: staging: comedi: gsc_hpdi: check dma_alloc_coherent() return value

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(+)

diff --git a/drivers/staging/comedi/drivers/gsc_hpdi.c b/drivers/staging/comedi/drivers/gsc_hpdi.c index 4bdf44d82879..dc62db1ee1dd 100644 --- 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 comedi_device *dev, 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 comedi_device *dev, 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");