[ 3.5.yuz extended stable ] Patch "staging: comedi: amplc_pc236: fix invalid register access" has been added to staging queue

[Herton Ronaldo Krzesinski]

This is a note to let you know that I have just added a patch titled

    staging: comedi: amplc_pc236: fix invalid register access

to the linux-3.5.y-queue branch of the 3.5.yuz extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.yuz tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

>From c988873fe416b83de10b47a9645f44511ec38316 Mon Sep 17 00:00:00 2001
From: Ian Abbott <abbotti at mev.co.uk>
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 <abbotti at mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
[ herton: devpriv is a macro on 3.5, just check dev->iobase ]
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 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 57ba322..1fe5ac9 100644
--- a/drivers/staging/comedi/drivers/amplc_pc236.c
+++ b/drivers/staging/comedi/drivers/amplc_pc236.c
@@ -479,7 +479,7 @@ static int pc236_attach(struct comedi_device *dev, struct comedi_devconfig *it)

 static void pc236_detach(struct comedi_device *dev)
 {
-	if (devpriv)
+	if (dev->iobase)
 		pc236_intr_disable(dev);
 	if (dev->irq)
 		free_irq(dev->irq, dev);
--
1.7.9.5