From a0419caba889d9a5f743a51b7cf9269c16c397a5 Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Wed, 3 Oct 2012 16:25:17 +0100 Subject: [PATCH] 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 --- drivers/staging/comedi/drivers/amplc_pc236.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/staging/comedi/drivers/amplc_pc236.c b/drivers/staging/comedi/drivers/amplc_pc236.c index 7972cadd403e..9a23d20938a5 100644 --- a/drivers/staging/comedi/drivers/amplc_pc236.c +++ b/drivers/staging/comedi/drivers/amplc_pc236.c @@ -468,7 +468,7 @@ 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) -- 2.39.5