From 2fd2bdfccae61efe18f6b92b6a45fbf936d75b48 Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Tue, 20 Aug 2013 11:50:19 +0100 Subject: [PATCH] staging: comedi: pcmuio: fix possible NULL deref on detach pcmuio_detach() is called by the comedi core even if pcmuio_attach() returned an error, so `dev->private` might be `NULL`. Check for that before dereferencing it. Also, as pointed out by Dan Carpenter, there is no need to check the pointer passed to `kfree()` is non-NULL, so remove that check. Signed-off-by: Ian Abbott Cc: Dan Carpenter Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/pcmuio.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/staging/comedi/drivers/pcmuio.c b/drivers/staging/comedi/drivers/pcmuio.c index f942455..67e2bb1 100644 --- a/drivers/staging/comedi/drivers/pcmuio.c +++ b/drivers/staging/comedi/drivers/pcmuio.c @@ -672,12 +672,13 @@ static void pcmuio_detach(struct comedi_device *dev) struct pcmuio_private *devpriv = dev->private; int i; - for (i = 0; i < PCMUIO_MAX_ASICS; ++i) { - if (devpriv->asics[i].irq) - free_irq(devpriv->asics[i].irq, dev); - } - if (devpriv && devpriv->sprivs) + if (devpriv) { + for (i = 0; i < PCMUIO_MAX_ASICS; ++i) { + if (devpriv->asics[i].irq) + free_irq(devpriv->asics[i].irq, dev); + } kfree(devpriv->sprivs); + } comedi_legacy_detach(dev); } -- 2.7.4