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From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Sakari Ailus <sakari.ailus@iki.fi>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Colin King <colin.king@canonical.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	linux-media@vger.kernel.org, kernel-janitors@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH][next] media: ispstat: don't dereference user_cfg before a null check
Date: Mon, 30 Apr 2018 10:26:25 -0500	[thread overview]
Message-ID: <9c1e7c1e-c391-4b91-7836-61a8b9d5489a@embeddedor.com> (raw)
In-Reply-To: <20180430151503.d3kq2zomil6uh2xf@valkosipuli.retiisi.org.uk>

Hi Sakari,

On 04/30/2018 10:15 AM, Sakari Ailus wrote:
>> Isn't there a guarantee that new_buf won't be NULL ? The new_buf pointer comes
>> from the parg variable in video_usercopy(), which should always point to a
>> valid buffer given that the ioctl number specifies a non-zero size.
> 
> Fair question. After looking at the code, I agree with you; there should be
> no reason to perform the check in the first place. It may have been that
> the function has been used differently in the past but the check should be
> rather removed now.
> 
> I'll drop the patch.
> 

Please, if the check isn't needed anymore, make sure it is removed.

This helps to reduce the number of false positives reported by static 
analyzers.

Thanks
--
Gustavo

WARNING: multiple messages have this Message-ID (diff)
From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Sakari Ailus <sakari.ailus@iki.fi>,
	Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Colin King <colin.king@canonical.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	linux-media@vger.kernel.org, kernel-janitors@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH][next] media: ispstat: don't dereference user_cfg before a null check
Date: Mon, 30 Apr 2018 15:26:25 +0000	[thread overview]
Message-ID: <9c1e7c1e-c391-4b91-7836-61a8b9d5489a@embeddedor.com> (raw)
In-Reply-To: <20180430151503.d3kq2zomil6uh2xf@valkosipuli.retiisi.org.uk>

Hi Sakari,

On 04/30/2018 10:15 AM, Sakari Ailus wrote:
>> Isn't there a guarantee that new_buf won't be NULL ? The new_buf pointer comes
>> from the parg variable in video_usercopy(), which should always point to a
>> valid buffer given that the ioctl number specifies a non-zero size.
> 
> Fair question. After looking at the code, I agree with you; there should be
> no reason to perform the check in the first place. It may have been that
> the function has been used differently in the past but the check should be
> rather removed now.
> 
> I'll drop the patch.
> 

Please, if the check isn't needed anymore, make sure it is removed.

This helps to reduce the number of false positives reported by static 
analyzers.

Thanks
--
Gustavo

  reply	other threads:[~2018-04-30 15:26 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-24 13:06 [PATCH][next] media: ispstat: don't dereference user_cfg before a null check Colin King
2018-04-24 13:06 ` Colin King
2018-04-26  8:37 ` Sakari Ailus
2018-04-26  8:37   ` Sakari Ailus
2018-04-26 10:03   ` Laurent Pinchart
2018-04-26 10:03     ` Laurent Pinchart
2018-04-30 15:15     ` Sakari Ailus
2018-04-30 15:15       ` Sakari Ailus
2018-04-30 15:26       ` Gustavo A. R. Silva [this message]
2018-04-30 15:26         ` Gustavo A. R. Silva

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