On 15/12/2019 01:33, Navid Emamdoost wrote:
In the implementation of gsc_hpdi_auto_attach(), the allocated dma
description is leaks in case of alignment error, or failure of
gsc_hpdi_setup_dma_descriptors() or comedi_alloc_subdevices(). Release
devpriv->dma_desc via dma_free_coherent().
Signed-off-by: Navid Emamdoost <navid.emamdoost@xxxxxxxxx>
Actually, there is no memory leak (although there is another problem
that I'll mention below). If the "auto_attach" handler
gsc_hpdi_auto_attach() returns an error, then the "detach" handler
gsc_hpdi_detach() will be called automatically to clean up. (This is
true for all comedi drivers). gsc_hpdi_detach() calls
gsc_hpdi_free_dma() to free the DMA buffers and DMA descriptors.
---
drivers/staging/comedi/drivers/gsc_hpdi.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/comedi/drivers/gsc_hpdi.c b/drivers/staging/comedi/drivers/gsc_hpdi.c
index 4bdf44d82879..c0c7047a6d1b 100644
--- a/drivers/staging/comedi/drivers/gsc_hpdi.c
+++ b/drivers/staging/comedi/drivers/gsc_hpdi.c
@@ -633,16 +633,17 @@ static int gsc_hpdi_auto_attach(struct comedi_device *dev,
if (devpriv->dma_desc_phys_addr & 0xf) {
dev_warn(dev->class_dev,
" dma descriptors not quad-word aligned (bug)\n");
- return -EIO;
+ retval = -EIO;
+ goto release_dma_desc;
}
retval = gsc_hpdi_setup_dma_descriptors(dev, 0x1000);
if (retval < 0)
- return retval;
+ goto release_dma_desc;
retval = comedi_alloc_subdevices(dev, 1);
if (retval)
- return retval;
+ goto release_dma_desc;
/* Digital I/O subdevice */
s = &dev->subdevices[0];
@@ -660,6 +661,15 @@ static int gsc_hpdi_auto_attach(struct comedi_device *dev,
s->cancel = gsc_hpdi_cancel;
return gsc_hpdi_init(dev);
+
+release_dma_desc:
+ if (devpriv->dma_desc)
+ dma_free_coherent(&pcidev->dev,
+ sizeof(struct plx_dma_desc) *
+ NUM_DMA_DESCRIPTORS,
+ devpriv->dma_desc,
+ devpriv->dma_desc_phys_addr);
+ return retval;
}
static void gsc_hpdi_detach(struct comedi_device *dev)
This patch could actually result in devpriv->dma_desc being freed twice
- once in the 'release_dma_desc:' code and again when gsc_hpdi_detach()
is called externally as part of the clean-up.
The real bug in the original code is that it does not check whether any
of the calls to dma_alloc_coherent() returned NULL. If any of the calls
to dma_alloc_coherent() returns NULL, gsc_hpdi_auto_attach() needs to
return an error (-ENOMEM). The subsequent call to gsc_hpdi_detach()
will then free whatever DMA coherent buffers where allocated.
--
-=( Ian Abbott <abbotti@xxxxxxxxx> || Web: www.mev.co.uk )=-
-=( MEV Ltd. is a company registered in England & Wales. )=-
-=( Registered number: 02862268. Registered address: )=-
-=( 15 West Park Road, Bramhall, STOCKPORT, SK7 3JZ, UK. )=-
_______________________________________________
devel mailing list
devel@xxxxxxxxxxxxxxxxxxxxxx
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
