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~7541^2~379 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=5a30fddcc9593086c26cef6496f757e262059cf6;p=firefly-linux-kernel-4.4.55.git staging: comedi: amplc_pc236: fix invalid register access during detach commit aaeb61a97b7159ebe30b18a422d04eeabfa8790b upstream. `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. 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 48246cd50d47..b4311bf66e6d 100644 --- a/drivers/staging/comedi/drivers/amplc_pc236.c +++ b/drivers/staging/comedi/drivers/amplc_pc236.c @@ -470,7 +470,7 @@ static int pc236_detach(struct comedi_device *dev) { printk(KERN_DEBUG "comedi%d: %s: detach\n", dev->minor, PC236_DRIVER_NAME); - if (devpriv) + if (dev->iobase) pc236_intr_disable(dev); if (dev->irq)