Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 33/34] staging: comedi: amplc_pc236: fix invalid register access during detach | Date | Mon, 29 Oct 2012 13:08:04 -0700 |
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3.0-stable review patch. If anyone has any objections, please let me know.
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From: Ian Abbott <abbotti@mev.co.uk>
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 <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/staging/comedi/drivers/amplc_pc236.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- 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_de { 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)
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