linux-kernel - Re: [PATCH RESEND] PM: domains: Fix return value of API dev_pm_get_subsys

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Message-ID: <2024111257-collide-finalist-7a0c@gregkh>
Date: Tue, 12 Nov 2024 12:46:30 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: Zijun Hu <zijun_hu@...oud.com>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>, Pavel Machek <pavel@....cz>,
	Len Brown <len.brown@...el.com>, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, Zijun Hu <quic_zijuhu@...cinc.com>,
	stable@...r.kernel.org
Subject: Re: [PATCH RESEND] PM: domains: Fix return value of API
 dev_pm_get_subsys_data()

On Mon, Oct 28, 2024 at 08:31:11PM +0800, Zijun Hu wrote:
> From: Zijun Hu <quic_zijuhu@...cinc.com>
> 
> dev_pm_get_subsys_data() has below 2 issues under condition
> (@dev->power.subsys_data != NULL):
> 
> - it will do unnecessary kzalloc() and kfree().

But that's ok, everything still works, right?

> - it will return -ENOMEM if the kzalloc() fails, that is wrong
>   since the kzalloc() is not needed.

But it's ok to return the proper error if the system is that broken.

> 
> Fixed by not doing kzalloc() and returning 0 for the condition.
> 
> Fixes: ef27bed1870d ("PM: Reference counting of power.subsys_data")
> Cc: stable@...r.kernel.org

Why is this relevant for stable kernels?

thanks,

greg k-h