Re: [PATCH 1/2] watchdog: Add Cadence WDT driver

[Guenter Roeck]

On 03/31/2014 03:30 AM, One Thousand Gnomes wrote:
> > +	wdt->cdns_wdt_notifier.notifier_call = &cdns_wdt_notify_sys;
> > +	/* Register the reboot notifier */
> > +	ret = register_reboot_notifier(&wdt->cdns_wdt_notifier);
> > +	if (ret != 0) {
> > +		dev_err(&pdev->dev, "cannot register reboot notifier err=%d)\n",
> > +			ret);
> > +		return ret;
>
> Your ordering is wrong. If the box reboots between here and the spin lock
> in it further down it'll crash in your notifier.
Not only that, the callback also ends up using watchdog_get_drvdata()
which is only set after registering the notifier.

Guenter

> As
>
> > +	spin_lock_init(&wdt->io_lock);
>
> is needed before the code your notifier calls will work.
>
> > +	dev_info(&pdev->dev, "Xilinx Watchdog Timer at %p with timeout %ds%s\n",
> > +		 wdt->regs, cdns_wdt_device->timeout,
> > +		 nowayout ? ", nowayout" : "");
>
> dev_dbg
>
> if every driver felt the need to announce itself on boot you'd have pages
> and pages of junk.
>
> Alan
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