linux-kernel - Re: [PATCH] [media] Siano: Use common error handling code in smsusb_init

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Message-ID: <20170920135605.sneukaioeabalkud@mwanda>
Date:   Wed, 20 Sep 2017 16:56:06 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     SF Markus Elfring <elfring@...rs.sourceforge.net>
Cc:     linux-media@...r.kernel.org,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] [media] Siano: Use common error handling code in
 smsusb_init_device()

On Wed, Sep 20, 2017 at 02:40:28PM +0200, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Wed, 20 Sep 2017 14:30:55 +0200
> 
> Add a jump target so that a bit of exception handling can be better
> reused at the end of this function.
> 
> This refactoring might fix also an error situation where the
> function "kfree" was not called after a software failure
> was noticed in two cases.
> 

No.  It doesn't fix a leak, it introduces a double free.  If
smscore_register_device() succeeds then mdev is freed when we call
smsusb_term_device(intf);  The call tree is:

smsusb_term_device()
 -> smscore_unregister_device()
    -> smscore_notify_clients()
       -> smsdvb_onremove()
          -> smsdvb_unregister_client()
             -> smsdvb_media_device_unregister()
                -> kfree(coredev->media_dev);

regards,
dan carpenter