Apple

On 1 sept. 2012, at 02:09, Jean Suisse wrote:

Hello,

I am stuck with a kernel panic, and thought I know which line of code causes it, I can't understand the source of the error.
The code is located in a network kernel extension.

In FirstFile.h file, I declare a structure and a function:

struct anObject
{
void** pointerArray;
};

void initObject (struct anObject* theObject);

In FirstFile.c I implement the function:

void initObject(struct anObject* theObject)
{
theObject->pointerArray = OSMalloc(….);
}

In SecondFile.c file, I declare a static variable :

static struct anObject myObject = { NULL };

and I call:
initObject(&myObject);

This will cause the kernel panic. Specifically the line with OSMalloc in initObject(…).

What I can tell :
- &myObject != NULL;
- &myObject->pointerArray == NULL;
- the OSMallocTag I use with OSMalloc is valid. And works for any other call
- The size I want to alloc is very reasonable (40 Bytes)

Also, I am wondering… could this be linked to the use of static variables ?
A few days ago, I decided to replace a dynamically allocated structure (OSMalloc) with a static variable structure that I would reuse. I did that for efficiency, since I found out that I was using the structure a lot, and I only needed one instance of the structure at any given time.
Well, I started to get kernel panics when passing the address of the structure to ctl_enqueuedata… solved by reverting back to a static pointer towards the OSMalloc'd structure...

Any idea on what's happening ?

Best regards,
Jean