linux-kernel - Re: [PATCH] regmap: debugfs: potentially duplicate the name string of the config

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Date:   Tue, 8 Sep 2020 16:35:59 +0100
From:   Mark Brown <broonie@...nel.org>
To:     Dafna Hirschfeld <dafna.hirschfeld@...labora.com>
Cc:     linux-kernel@...r.kernel.org, rafael@...nel.org,
        gregkh@...uxfoundation.org, enric.balletbo@...labora.com,
        kernel@...labora.com, dafna3@...il.com
Subject: Re: [PATCH] regmap: debugfs: potentially duplicate the name string
 of the config

On Tue, Sep 08, 2020 at 05:28:59PM +0200, Dafna Hirschfeld wrote:
> In function regmap_debugfs_init the name of the regmap_config is assigned
> in a node of regmap_debugfs_early_list to be used later after regmap
> is initialized. It is unknown how and when the name is allocated and freed.
> Therefore the name should be copied to the node using 'kstrdup_const'.

It does not follow that the name should be copied, it equally follows
(and is expected by the API given that the common case is that the name
is a static string assigned at build time) that the caller should not
free the string while the regmap is active.

> This fixes an error
> "debugfs: Directory 'dummy-' with parent 'regmap' already present!"
> where the name was freed in function of_syscon_register before
> it was accessed.

Fix the caller.  It is *very* much unclear to me why a syscon would be
assigning a name for a regmap it creates in the first place.

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