2024-01-22 11:47:44

by Rafael J. Wysocki

Subject: [PATCH v1 08/12] PM: sleep: stats: Use locking in dpm_save_failed_dev()

From: Rafael J. Wysocki <[email protected]>

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 <[email protected]>
---
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)

2024-01-25 09:20:14

by Stanislaw Gruszka

Subject: Re: [PATCH v1 08/12] PM: sleep: stats: Use locking in dpm_save_failed_dev()

On Mon, Jan 22, 2024 at 12:33:53PM +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <[email protected]>
>
> 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 <[email protected]>
Reviewed-by: Stanislaw Gruszka <[email protected]>

> ---
> 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)
>
>
>
>