diff options
| author | Ian Abbott <abbotti@mev.co.uk> | 2013-06-28 16:09:17 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-07-23 21:27:50 (GMT) |
| commit | 725a70d8a68ef5368652c0c49631fefb361d62cf (patch) | |
| tree | 71dfe83245b4881ae61c9c59edc027e9c73262f4 | |
| parent | c383e2d6dacf0b6fdd40fbaf044e235cac54a20f (diff) | |
| download | linux-fsl-qoriq-725a70d8a68ef5368652c0c49631fefb361d62cf.tar.xz | |
staging: comedi: ni_labpc: fix possible double-free of dma_buffer
If `labpc_attach()` allocates memory for `devpriv->dma_buffer` but fails
to request a DMA channel, it frees `devpriv->dma_buffer` but leaves the
pointer set. Later, `labpc_detach()` frees `devpriv->dma_buffer` again,
which means it has been freed twice in this case.
Fix it by only setting `devpriv->dma_buffer` in `labpc_attach()` if the
DMA channel was requested successfully.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/staging/comedi/drivers/ni_labpc.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/staging/comedi/drivers/ni_labpc.c b/drivers/staging/comedi/drivers/ni_labpc.c index 3e95ac5..4ff1ed0 100644 --- a/drivers/staging/comedi/drivers/ni_labpc.c +++ b/drivers/staging/comedi/drivers/ni_labpc.c @@ -1712,13 +1712,15 @@ static int labpc_attach(struct comedi_device *dev, struct comedi_devconfig *it) #ifdef CONFIG_ISA_DMA_API if (dev->irq && (dma_chan == 1 || dma_chan == 3)) { - devpriv->dma_buffer = kmalloc(dma_buffer_size, - GFP_KERNEL | GFP_DMA); - if (devpriv->dma_buffer) { + void *dma_buffer = kmalloc(dma_buffer_size, + GFP_KERNEL | GFP_DMA); + + if (dma_buffer) { ret = request_dma(dma_chan, dev->board_name); if (ret == 0) { unsigned long dma_flags; + devpriv->dma_buffer = dma_buffer; devpriv->dma_chan = dma_chan; devpriv->dma_addr = virt_to_bus(devpriv->dma_buffer); @@ -1728,7 +1730,7 @@ static int labpc_attach(struct comedi_device *dev, struct comedi_devconfig *it) set_dma_mode(devpriv->dma_chan, DMA_MODE_READ); release_dma_lock(dma_flags); } else { - kfree(devpriv->dma_buffer); + kfree(dma_buffer); } } } |