Re: [S390] cio: kernel stack overflow.

[daw@cs.berkeley.edu (David Wagner)]

Thanks for pointing out that in most cases there was immediately
preceding code that zeroes out the whole struct using kzalloc() or
memset(.., 0, ..).  Sorry that I overlooked that; my mistake.  That
takes care of all but one of these.  But in the interests of caution,
let me ask about the following one:

Martin Schwidefsky  wrote:
>-		cdev->id = (struct ccw_device_id) {
>-			.cu_type   = cdev->private->senseid.cu_type,
>-			.cu_model  = cdev->private->senseid.cu_model,
>-			.dev_type  = cdev->private->senseid.dev_type,
>-			.dev_model = cdev->private->senseid.dev_model,
>-		};
>+		cdev->id.cu_type   = cdev->private->senseid.cu_type;
>+		cdev->id.cu_model  = cdev->private->senseid.cu_model;
>+		cdev->id.dev_type  = cdev->private->senseid.dev_type;
>+		cdev->id.dev_model = cdev->private->senseid.dev_model;

I don't see any obvious place that zeroes out cdev->id.
In particular, it looks like cdev->id.match_flags and .driver_info
are never cleared (i.e., they retain whatever old garbage they had
before).  More importantly, if anyone ever adds any more fields to
struct ccw_device_id, then they will also be retain old garbage values,
which is a maintenance pitfall.  Is this right, or did I miss something
again?