[External][PATCH] power: supply: bq2415x: fix deadlock in bq2415x_set_autotimer

[External][PATCH] power: supply: bq2415x: fix deadlock in bq2415x_set_autotimer

[Kezhou Li]

From: "Kezhou Li" <kezhou.li@tinno.com>

The bq2415x_timer_error called by bq2415x_timer_work when some error
happens, and then calls cancel_delayed_work_sync(&bq->work). Finally
this function is waiting for the work to finish but the work is
waiting for the return of the function. So it causes a deadlock.

Signed-off-by: Kezhou Li <kezhou.li@tinno.com>
---
 drivers/power/supply/bq2415x_charger.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/power/supply/bq2415x_charger.c b/drivers/power/supply/bq2415x_charger.c
index 5724001..7889edb 100644
--- a/drivers/power/supply/bq2415x_charger.c
+++ b/drivers/power/supply/bq2415x_charger.c
@@ -862,8 +862,6 @@ static void bq2415x_set_autotimer(struct bq2415x_device *bq, int state)
 		schedule_delayed_work(&bq->work, BQ2415X_TIMER_TIMEOUT * HZ);
 		bq2415x_exec_command(bq, BQ2415X_TIMER_RESET);
 		bq->timer_error = NULL;
-	} else {
-		cancel_delayed_work_sync(&bq->work);
 	}
 
 	mutex_unlock(&bq2415x_timer_mutex);
-- 
1.9.1

Re: [External][PATCH] power: supply: bq2415x: fix deadlock in bq2415x_set_autotimer

[Sebastian Reichel]

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Hi,

On Mon, Jun 21, 2021 at 08:14:20PM +0800, Kezhou Li wrote:
> From: "Kezhou Li" <kezhou.li@tinno.com>
> 
> The bq2415x_timer_error called by bq2415x_timer_work when some error
> happens, and then calls cancel_delayed_work_sync(&bq->work). Finally
> this function is waiting for the work to finish but the work is
> waiting for the return of the function. So it causes a deadlock.
> 
> Signed-off-by: Kezhou Li <kezhou.li@tinno.com>
> ---

The patch is not correct, since bq2415x_sysfs_set_timer() should
call cancel_delayed_work_sync() for the "off" case.

-- Sebastian

>  drivers/power/supply/bq2415x_charger.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/power/supply/bq2415x_charger.c b/drivers/power/supply/bq2415x_charger.c
> index 5724001..7889edb 100644
> --- a/drivers/power/supply/bq2415x_charger.c
> +++ b/drivers/power/supply/bq2415x_charger.c
> @@ -862,8 +862,6 @@ static void bq2415x_set_autotimer(struct bq2415x_device *bq, int state)
>  		schedule_delayed_work(&bq->work, BQ2415X_TIMER_TIMEOUT * HZ);
>  		bq2415x_exec_command(bq, BQ2415X_TIMER_RESET);
>  		bq->timer_error = NULL;
> -	} else {
> -		cancel_delayed_work_sync(&bq->work);
>  	}
>  
>  	mutex_unlock(&bq2415x_timer_mutex);
> -- 
> 1.9.1
> 

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