Re: [PATCH v6 02/24] x86/resctrl: kfree() rmid_ptrs from rdtgroup_exit()

Moger, Babu
2023-10-04T18:00:46Z

Hi James,

On 9/14/23 12:21, James Morse wrote:
> rmid_ptrs[] is allocated from dom_data_init() but never free()d.
>
> While the exit text ends up in the linker script's DISCARD section,
> the direction of travel is for resctrl to be/have loadable modules.
>
> Add resctrl_exit_mon_l3_config() to cleanup any memory allocated
> by rdt_get_mon_l3_config().
>
> There is no reason to backport this to a stable kernel.
>
> Signed-off-by: James Morse <james.morse@arm.com>
> ---
> Changes since v5:
> * This patch is new
> ---
> arch/x86/kernel/cpu/resctrl/internal.h | 1 +
> arch/x86/kernel/cpu/resctrl/monitor.c | 10 ++++++++++
> arch/x86/kernel/cpu/resctrl/rdtgroup.c | 5 +++++
> 3 files changed, 16 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index 85ceaf9a31ac..57cf1e6a57bd 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -537,6 +537,7 @@ void closid_free(int closid);
> int alloc_rmid(void);
> void free_rmid(u32 rmid);
> int rdt_get_mon_l3_config(struct rdt_resource *r);
> +void resctrl_exit_mon_l3_config(struct rdt_resource *r);
> bool __init rdt_cpu_has(int flag);
> void mon_event_count(void *info);
> int rdtgroup_mondata_show(struct seq_file *m, void *arg);
> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
> index ded1fc7cb7cb..cfb3f632a4b2 100644
> --- a/arch/x86/kernel/cpu/resctrl/monitor.c
> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
> @@ -741,6 +741,16 @@ static int dom_data_init(struct rdt_resource *r)
> return 0;
> }
>
> +void resctrl_exit_mon_l3_config(struct rdt_resource *r)
> +{
> + mutex_lock(&rdtgroup_mutex);
> +
> + kfree(rmid_ptrs);
> + rmid_ptrs = NULL;
> +
> + mutex_unlock(&rdtgroup_mutex);
> +}

What is the need for passing "rdt_resource *r" here?
Is mutex_lock required?

Thanks
Babu