linux-kernel - Re: [PATCH 02/11] virtio_console: Less function calls in init

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Date:   Wed, 21 Sep 2016 17:40:38 +0530
From:   Amit Shah <amit.shah@...hat.com>
To:     SF Markus Elfring <elfring@...rs.sourceforge.net>
Cc:     virtualization@...ts.linux-foundation.org,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        Rusty Russell <rusty@...tcorp.com.au>,
        LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org,
        Julia Lawall <julia.lawall@...6.fr>
Subject: Re: [PATCH 02/11] virtio_console: Less function calls in init_vqs()
 after error detection

Hi,

On (Wed) 14 Sep 2016 [16:01:28], SF Markus Elfring wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Wed, 14 Sep 2016 14:00:35 +0200
> 
> The kfree() function was called in up to five cases
> by the init_vqs() function during error handling even if
> the passed variable contained a null pointer.
> 
> * Return directly after a call of the function "kmalloc_array" failed
>   at the beginning.
> 
> * Split a condition check for memory allocation failures so that
>   each pointer from these function calls will be checked immediately.
> 
>   See also background information:
>   Topic "CWE-754: Improper check for unusual or exceptional conditions"
>   Link: https://cwe.mitre.org/data/definitions/754.html
> 
> * Adjust jump targets according to the Linux coding style convention.

So I've seen this series and I'm not yet sure how I feel about the
patches - f.e. in this one, it adds more lines than it removes to
achieve the same effect.  I think the code is currently more readable
than after these changes.  And even if kfree is called multiple times,
it isn't a huge bother -- it's error case anyway, very unlikely to
trigger, but keeps everything very readble.


		Amit