Re: [PATCH] 2.4.10-pre13: ATM drivers cause panic

[Alan Cox]

> seems a couple of spin_lock(s) and a spin_unlock was missing.
> Why didn't this problem show up with earlier releases ???
> Anyways, please find a (quick) patch below. It would be great if this patch or
> any other similar could make it into the next release!

How about

static struct atm_dev *alloc_atm_dev(const char *type)
{
 	struct atm_dev *dev;

	dev = kmalloc(sizeof(*dev),GFP_KERNEL);
	if (!dev) return NULL;
	memset(dev,0,sizeof(*dev));
	dev->type = type;
        dev->signal = ATM_PHY_SIG_UNKNOWN;
        dev->link_rate = ATM_OC3_PCR;
        dev->next = NULL;

        spin_lock(&atm_dev_lock);

        dev->prev = last_dev;

	if (atm_devs) last_dev->next = dev;
	else atm_devs = dev;
	last_dev = dev;
	spin_unlock(&atm_dev_lock);
	return dev;
}

instead. That seems to fix alloc_atm_dev safely. Refcounting wants adding
to atm_dev objects too, its impossible currently to make atm_find_dev
remotely safe

Alan