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Date:   Mon, 3 Apr 2023 17:23:55 +0200
From:   Pavel Machek <pavel@ucw.cz>
To:     "H. Nikolaus Schaller" <hns@goldelico.com>
Cc:     Marek =?iso-8859-1?Q?Beh=FAn?= <kabel@kernel.org>,
        Lee Jones <lee@kernel.org>, linux-leds@vger.kernel.org,
        linux-kernel@vger.kernel.org, letux-kernel@openphoenux.org,
        NeilBrown <neilb@suse.de>,
        Linus Walleij <linus.walleij@linaro.org>
Subject: Re: [PATCH] leds: tca6507: fix error handling of using
 fwnode_property_read_string
Message-ID: <ZCrviz6zNXJpmkN7@duo.ucw.cz>
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On Sun 2023-04-02 13:12:59, H. Nikolaus Schaller wrote:
> Commit 96f524105b9c ("leds: tca6507: use fwnode API instead of OF")
>=20
> changed to fwnode API but did not take into account that a missing proper=
ty
> "linux,default-trigger" now seems to return an error and as a side effect
> sets value to -1. This seems to be different from of_get_property() which
> always returned NULL in any case of error.
>=20
> Neglecting this side-effect leads to
>=20
> [   11.201965] Unable to handle kernel paging request at virtual address =
ffffffff when read
>=20
> in the strcmp() of led_trigger_set_default() if there is no led-trigger
> defined in the DTS.
>=20
> I don't know if this was recently introduced somewhere in the fwnode lib
> or if the effect was missed in initial testing. Anyways it seems to be a
> bug to ignore the error return value of an optional value here in the
> driver.
>=20
> Fixes: 96f524105b9c ("leds: tca6507: use fwnode API instead of OF")
> Cc: Marek Beh=FAn <kabel@kernel.org>
> Cc: NeilBrown <neilb@suse.de>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>

Acked-by: Pavel Machek <pavel@ucw.cz>

BR,							Pavel
--=20
People of Russia, stop Putin before his war on Ukraine escalates.

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