linux-kernel - Re: [PATCH v2] PM: domains: Ensure genpd_debugfs

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Date:   Tue, 5 Jul 2022 19:37:23 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Hsin-Yi Wang <hsinyi@...omium.org>
Cc:     "Rafael J . Wysocki" <rafael@...nel.org>,
        Kevin Hilman <khilman@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Pavel Machek <pavel@....cz>, Len Brown <len.brown@...el.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Pin-yen Lin <treapking@...omium.org>, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] PM: domains: Ensure genpd_debugfs_dir exists before
 remove

On Wed, Jul 06, 2022 at 01:16:49AM +0800, Hsin-Yi Wang wrote:
> Both genpd_debug_add() and genpd_debug_remove() may be called
> indirectly by other drivers while genpd_debugfs_dir is not yet
> set. For example, drivers can call pm_genpd_init() in probe or
> pm_genpd_init() in probe fail/cleanup path:
> 
> pm_genpd_init()
>  --> genpd_debug_add()
> 
> pm_genpd_remove()
>  --> genpd_remove()
>    --> genpd_debug_remove()
> 
> At this time, genpd_debug_init() may not yet be called.
> 
> genpd_debug_add() checks that if genpd_debugfs_dir is NULL, it
> will return directly. Make sure this is also checked
> in pm_genpd_remove(), otherwise components under debugfs root
> which has the same name as other components under pm_genpd may
> be accidentally removed, since NULL represents debugfs root.
> 
> Fixes: 718072ceb211 ("PM: domains: create debugfs nodes when adding power domains")
> Signed-off-by: Hsin-Yi Wang <hsinyi@...omium.org>
> ---
> v1->v2: Add more context in commit message

Reviewed-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>