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Subject: Re: [PATCH v2 0/1] Open questions
To:     "Dr. Philipp Tomsich" <philipp.tomsich@theobroma-systems.com>,
        Jakob Unterwurzacher <jakob.unterwurzacher@theobroma-systems.com>
Cc:     Martin Elshuber <martin.elshuber@theobroma-systems.com>,
        Wolfgang Grandegger <wg@grandegger.com>,
        linux-can@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20180313173520.21257-1-jakob.unterwurzacher@theobroma-systems.com>
 <e0c8c001-f66b-2e8e-d9ec-89a0db9c5853@theobroma-systems.com>
 <06378497-1ACE-4333-810F-4E3E4706CCD5@theobroma-systems.com>
From:   Marc Kleine-Budde <mkl@pengutronix.de>
Message-ID: <ba3f53b1-e8bb-4c61-b486-19b9865d6e22@pengutronix.de>
Date:   Tue, 13 Mar 2018 18:48:40 +0100
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From: Marc Kleine-Budde <mkl@pengutronix.de>
To: "Dr. Philipp Tomsich" <philipp.tomsich@theobroma-systems.com>,
 Jakob Unterwurzacher <jakob.unterwurzacher@theobroma-systems.com>
Cc: Martin Elshuber <martin.elshuber@theobroma-systems.com>,
 Wolfgang Grandegger <wg@grandegger.com>, linux-can@vger.kernel.org,
 linux-kernel@vger.kernel.org
Message-ID: <ba3f53b1-e8bb-4c61-b486-19b9865d6e22@pengutronix.de>
Subject: Re: [PATCH v2 0/1] Open questions
References: <20180313173520.21257-1-jakob.unterwurzacher@theobroma-systems.com>
 <e0c8c001-f66b-2e8e-d9ec-89a0db9c5853@theobroma-systems.com>
 <06378497-1ACE-4333-810F-4E3E4706CCD5@theobroma-systems.com>
In-Reply-To: <06378497-1ACE-4333-810F-4E3E4706CCD5@theobroma-systems.com>

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On 03/13/2018 06:42 PM, Dr. Philipp Tomsich wrote:
>=20
>> On 13 Mar 2018, at 18:40, Jakob Unterwurzacher
>> <jakob.unterwurzacher@theobroma-systems.com
>> <mailto:jakob.unterwurzacher@theobroma-systems.com>> wrote:
>>
>> >> + =C2=A0=C2=A0=C2=A0/* get the urb context */
>> >> + =C2=A0=C2=A0=C2=A0if (WARN_ON(!context))
>> >> + =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0return;
>> >
>> > Can this happen?
>>
>> Not unless there is a bug in the code. But we want to get a message
>> before dereferencing a pointer.
>=20
> Why not use BUG_ON(!context)?

As this will halt the whole system.

Marc

--=20
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |


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