linux-kernel - Re: [PATCH v3 05/10] device property: Add a function to obtain a node's prefix

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Message-ID: <20190902072924.GI5475@paasikivi.fi.intel.com>
Date:   Mon, 2 Sep 2019 10:29:24 +0300
From:   Sakari Ailus <sakari.ailus@...ux.intel.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Petr Mladek <pmladek@...e.com>, linux-kernel@...r.kernel.org,
        rafael@...nel.org, linux-acpi@...r.kernel.org,
        devicetree@...r.kernel.org, Rob Herring <robh@...nel.org>
Subject: Re: [PATCH v3 05/10] device property: Add a function to obtain a
 node's prefix

Hi Andy,

On Fri, Aug 30, 2019 at 03:46:57PM +0300, Andy Shevchenko wrote:
> On Thu, Aug 29, 2019 at 01:10:38PM +0300, Sakari Ailus wrote:
> > The prefix is used for printing purpose before a node, and it also works
> > as a separator between two nodes.
> 
> > +	/* Is this the root node? */
> > +	parent = fwnode_get_parent(fwnode);
> > +	if (!parent)
> > +		return "";
> > +
> > +	/* Is this 2nd node from the root? */
> > +	parent = fwnode_get_next_parent(parent);
> > +	if (!parent)
> 
> Can we theoretically have a case when we got parent != NULL and thus taken
> reference, while the 2nd one is NULL and we leak reference here (and in all
> similar places)?

fwnode_get_next_parent() releases that reference unconditionally.

-- 
Sakari Ailus
sakari.ailus@...ux.intel.com