linux-kernel - Re: [PATCH] PM: EM: Fix memory leak in em_create

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Message-ID: <28e46f37-54be-4c28-a7a8-2b3e80a8cd30@igalia.com>
Date: Thu, 8 Jan 2026 14:44:38 +0900
From: Changwoo Min <changwoo@...lia.com>
To: Malaya Kumar Rout <mrout@...hat.com>, linux-kernel@...r.kernel.org
Cc: malayarout91@...il.com, Lukasz Luba <lukasz.luba@....com>,
 "Rafael J. Wysocki" <rafael@...nel.org>, Pavel Machek <pavel@...nel.org>,
 Len Brown <lenb@...nel.org>, linux-pm@...r.kernel.org
Subject: Re: [PATCH] PM: EM: Fix memory leak in em_create_pd() error path

Thanks, Malaya, for the bug fix. This makes sense to me.

Reviewed-by:  Changwoo Min <changwoo@...lia.com>

On 1/5/26 7:37 PM, Malaya Kumar Rout wrote:
> When ida_alloc() fails in em_create_pd(), the function returns without
> freeing the previously allocated 'pd' structure, leading to a memory leak.
> The 'pd' pointer is allocated either at line 436 (for CPU devices with
> cpumask) or line 442 (for other devices) using kzalloc().
> 
> Additionally, the function incorrectly returns -ENOMEM when ida_alloc()
> fails, ignoring the actual error code returned by ida_alloc(), which can
> fail for reasons other than memory exhaustion.
> 
> Fix both issues by:
> 1. Freeing the 'pd' structure with kfree() when ida_alloc() fails
> 2. Returning the actual error code from ida_alloc() instead of -ENOMEM
> 
> This ensures proper cleanup on the error path and accurate error reporting.
> 
> Fixes: cbe5aeedecc7 ("PM: EM: Assign a unique ID when creating a performance domain")
> Signed-off-by: Malaya Kumar Rout <mrout@...hat.com>
> ---
>   kernel/power/energy_model.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c
> index 11af9f64aa82..5b055cbe5341 100644
> --- a/kernel/power/energy_model.c
> +++ b/kernel/power/energy_model.c
> @@ -449,8 +449,10 @@ static int em_create_pd(struct device *dev, int nr_states,
>   	INIT_LIST_HEAD(&pd->node);
>   
>   	id = ida_alloc(&em_pd_ida, GFP_KERNEL);
> -	if (id < 0)
> -		return -ENOMEM;
> +	if (id < 0) {
> +		kfree(pd);
> +		return id;
> +	}
>   	pd->id = id;
>   
>   	em_table = em_table_alloc(pd);