From: Ian Abbott Date: Wed, 3 Oct 2012 15:25:17 +0000 (+0100) Subject: staging: comedi: amplc_pc236: fix invalid register access during detach X-Git-Tag: firefly_0821_release~3680^2~1713^2~16 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=aaeb61a97b7159ebe30b18a422d04eeabfa8790b;p=firefly-linux-kernel-4.4.55.git staging: comedi: amplc_pc236: fix invalid register access during detach `pc236_detach()` is called by the comedi core if it attempted to attach a device and failed. `pc236_detach()` calls `pc236_intr_disable()` if the comedi device private data pointer (`devpriv`) is non-null. This test is insufficient as `pc236_intr_disable()` accesses hardware registers and the attach routine may have failed before it has saved their I/O base addresses. Fix it by checking `dev->iobase` is non-zero before calling `pc236_intr_disable()` as that means the I/O base addresses have been saved and the hardware registers can be accessed. It also implies the comedi device private data pointer is valid, so there is no need to check it. Cc: # 3.5.x, 3.6.x Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/comedi/drivers/amplc_pc236.c b/drivers/staging/comedi/drivers/amplc_pc236.c index eacb5e4735d7..36768b2b30ae 100644 --- a/drivers/staging/comedi/drivers/amplc_pc236.c +++ b/drivers/staging/comedi/drivers/amplc_pc236.c @@ -573,9 +573,8 @@ static int __devinit pc236_attach_pci(struct comedi_device *dev, static void pc236_detach(struct comedi_device *dev) { const struct pc236_board *thisboard = comedi_board(dev); - struct pc236_private *devpriv = dev->private; - if (devpriv) + if (dev->iobase) pc236_intr_disable(dev); if (dev->irq) free_irq(dev->irq, dev);