linux-kernel - Re: [PATCH v4] cpufreq: amd-pstate: fix the memory to free after epp exist

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Message-ID: <CAJZ5v0gqTnj4Dk844gMMG+rnBvbpA_dGErghTM1PokaDScdBSQ@mail.gmail.com>
Date: Thu, 16 May 2024 10:42:17 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: "Yuan, Perry" <Perry.Yuan@....com>, "zhida312@...look.com" <zhida312@...look.com>
Cc: "rafael@...nel.org" <rafael@...nel.org>, "viresh.kumar@...aro.org" <viresh.kumar@...aro.org>, 
	Peng Ma <andypma@...cent.com>, "Huang, Ray" <Ray.Huang@....com>, 
	"Shenoy, Gautham Ranjal" <gautham.shenoy@....com>, "Limonciello, Mario" <Mario.Limonciello@....com>, 
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>, 
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4] cpufreq: amd-pstate: fix the memory to free after epp exist

On Thu, May 16, 2024 at 10:28 AM Yuan, Perry <Perry.Yuan@....com> wrote:
>
> [AMD Official Use Only - AMD Internal Distribution Only]
>
> > -----Original Message-----
> > From: zhida312@...look.com <zhida312@...look.com>
> > Sent: Thursday, May 16, 2024 2:31 PM
> > To: rafael@...nel.org; viresh.kumar@...aro.org
> > Cc: Peng Ma <andypma@...cent.com>; Huang, Ray <Ray.Huang@....com>;
> > Shenoy, Gautham Ranjal <gautham.shenoy@....com>; Limonciello, Mario
> > <Mario.Limonciello@....com>; Yuan, Perry <Perry.Yuan@....com>; linux-
> > pm@...r.kernel.org; linux-kernel@...r.kernel.org
> > Subject: [PATCH v4] cpufreq: amd-pstate: fix the memory to free after epp
> > exist
> >
> > From: andypma <andypma.tencent.com>

The name and e-mail address in the From: header must be the same as in
the Signed-off-by tag, so I've fixed that up.

> > the cpudata memory from kzmalloc in epp init function is not free after epp
> > exist, so we should free it.
> >
> > Signed-off-by: Peng Ma <andypma@...cent.com>
> >
> > Changes from v3 to v4:
> >       update subject used git command "git format-patch -1 -v x"
> >
> > Changes from v2 to v3:
> >       update Signed-off-by to Peng Ma <andypma@...cent.com>.
> >       set a space between if and "(".
> >
> > Changes from v1 to v2:
> >       check whether it is empty before releasing
> >       set driver_data is NULL after free
> > ---
> >  drivers/cpufreq/amd-pstate.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> > index 6a342b0c0140..1b7e82a0ad2e 100644
> > --- a/drivers/cpufreq/amd-pstate.c
> > +++ b/drivers/cpufreq/amd-pstate.c
> > @@ -1441,6 +1441,13 @@ static int amd_pstate_epp_cpu_init(struct
> > cpufreq_policy *policy)
> >
> >  static int amd_pstate_epp_cpu_exit(struct cpufreq_policy *policy)  {
> > +     struct amd_cpudata *cpudata = policy->driver_data;
> > +
> > +     if (cpudata) {
> > +             kfree(cpudata);
> > +             policy->driver_data = NULL;
> > +     }

This does not need to be conditional, because you can pass NULL to
kfree(), but it is correct and since Mario has ACKed it ->

> > +
> >       pr_debug("CPU %d exiting\n", policy->cpu);
> >       return 0;
> >  }
> > --
> > 2.41.0
>
> Looks good now
>
> Reviewed-by: Perry Yuan <Perry.Yuan@....com>

-> applied as 6.10 material (with edited subject and changelog).

Thanks!