[ Follow upstream commit aaeb61a97b7159ebe30b18a422d04eeabfa8790b ] `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 <[email protected]> --- This patch is for the stable 3.4 kernel. --- 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 7972cad..9a23d20 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) -- 1.8.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
