linux-kernel - Re: [PATCH 4/5] staging: comedi: usbduxsigma: Split a condition check in usbduxsigma_alloc_usb

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Message-ID: <45ac6168-19a8-0864-3b69-2d2409e2b44f@mev.co.uk>
Date:   Thu, 8 Dec 2016 12:51:40 +0000
From:   Ian Abbott <abbotti@....co.uk>
To:     SF Markus Elfring <elfring@...rs.sourceforge.net>,
        devel@...verdev.osuosl.org, Chris Cesare <chris.cesare@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        H Hartley Sweeten <hsweeten@...ionengravers.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH 4/5] staging: comedi: usbduxsigma: Split a condition check
 in usbduxsigma_alloc_usb_buffers()

On 08/12/16 11:37, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Thu, 8 Dec 2016 11:15:40 +0100
>
> The functions "kcalloc" and "kzalloc" were called in four cases by the
> function "usbduxsigma_alloc_usb_buffers" without checking immediately
> if they succeded.
> This issue was detected by using the Coccinelle software.
>
> Allocated memory was also not released if one of these function
> calls failed.
>
> * Reduce memory allocation sizes for two function calls.
>
> * Split a condition check for memory allocation failures.
>
> * Add more exception handling.
>
> Fixes: 65989c030bbca96be45ed137f6384dbd46030d10 ("staging: comedi: usbduxsigma: factor usb buffer allocation out of (*probe)")
>
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---
>  drivers/staging/comedi/drivers/usbduxsigma.c | 61 ++++++++++++++++++++++------
>  1 file changed, 49 insertions(+), 12 deletions(-)

My comments on PATCH 2/5 about how comedi drivers handle clean-up apply 
to this patch too.  So this patch will cause an Oops in the unlikely 
event of running out of memory during buffer allocation.

-- 
-=( Ian Abbott @ MEV Ltd.    E-mail: <abbotti@....co.uk> )=-
-=(                          Web: http://www.mev.co.uk/  )=-