On Mon, Jan 22, 2024 at 12:33:53PM +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> Because dpm_save_failed_dev() may be called simultaneously by multiple
> failing device PM functions, the state of the suspend_stats fields
> updated by it may become inconsistent.
>
> Prevent that from happening by using a lock in dpm_save_failed_dev().
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
> ---
> kernel/power/main.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> Index: linux-pm/kernel/power/main.c
> ===================================================================
> --- linux-pm.orig/kernel/power/main.c
> +++ linux-pm/kernel/power/main.c
> @@ -323,13 +323,18 @@ struct suspend_stats {
> };
>
> static struct suspend_stats suspend_stats;
> +static DEFINE_MUTEX(suspend_stats_lock);
>
> void dpm_save_failed_dev(const char *name)
> {
> + mutex_lock(&suspend_stats_lock);
> +
> strscpy(suspend_stats.failed_devs[suspend_stats.last_failed_dev],
> name, sizeof(suspend_stats.failed_devs[0]));
> suspend_stats.last_failed_dev++;
> suspend_stats.last_failed_dev %= REC_FAILED_NUM;
> +
> + mutex_unlock(&suspend_stats_lock);
> }
>
> void dpm_save_failed_step(enum suspend_stat_step step)
>
>
>
>