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

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Message-ID: <CAJZ5v0j+Lz7ePtfbcVSyRqNPwLQNDoPT9zQ+a=7JL0S0RSR90Q@mail.gmail.com>
Date: Thu, 8 Jan 2026 16:56:52 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Changwoo Min <changwoo@...lia.com>, Malaya Kumar Rout <mrout@...hat.com>
Cc: linux-kernel@...r.kernel.org, malayarout91@...il.com, 
	Lukasz Luba <lukasz.luba@....com>, linux-pm@...r.kernel.org
Subject: Re: [PATCH] PM: EM: Fix memory leak in em_create_pd() error path

On Thu, Jan 8, 2026 at 6:44 AM Changwoo Min <changwoo@...lia.com> wrote:
>
> Thanks, Malaya, for the bug fix. This makes sense to me.
>
> Reviewed-by:  Changwoo Min <changwoo@...lia.com>

Applied as 6.19-rc material, thanks!

> 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);
>
>