linux-kernel - Re: [PATCH v2 06/16] watchdog: hpwdt: drop warning after calling watchdog_init

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Message-ID: <20190416205003.GA8268@kunai>
Date:   Tue, 16 Apr 2019 22:50:03 +0200
From:   Wolfram Sang <wsa@...-dreams.de>
To:     Jerry Hoemann <jerry.hoemann@....com>
Cc:     Wolfram Sang <wsa+renesas@...g-engineering.com>,
        linux-watchdog@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        Guenter Roeck <linux@...ck-us.net>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 06/16] watchdog: hpwdt: drop warning after calling
 watchdog_init_timeout

Hi Jerry,

> I applied patches 1,2 & 6 in testing.
> 
> Note, that hpwdt is passing NULL as the third parameter to watchdog_init_timeout().
> 
> The second patch in this series is using "dev" as input to dev_err and dev_warn.
> 
> This results in the following in dmesg when trying to load hpwdt w/ an invalid soft_margin:
> 
> 
> [   80.848160] (NULL device *): driver supplied timeout (4294967295) out of range
> [   80.855429] (NULL device *): falling back to default timeout (30)

Thank you for this report. Yes, using 'dev' blindly is a bug.

> if the call in hpwdt driver is changed to:
> 
> 	if (watchdog_init_timeout(&hpwdt_dev, soft_margin, &dev->dev))
> 
> 
> We see the message like we'd desire:
> 
> [ 2061.167100] hpwdt 0000:01:00.0: driver supplied timeout (4294967295) out of range
> [ 2061.174633] hpwdt 0000:01:00.0: falling back to default timeout (30)

The above observation makes sense, but I think we should fix the core
code and not the hpwdt driver. My suggestion would be to add something
like this to watchdog_init_timeout():

	struct device *err_dev = dev ?: wdd->parent;

And then use err_dev for all the printing. Guenter?

Regards,

   Wolfram


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