Re: [PATCH v20 01/10] power: reset: reboot-mode: Remove devres based allocations

[Sebastian Reichel]

Hi,

On Wed, Mar 04, 2026 at 11:33:01PM +0530, Shivendra Pratap wrote:
> Devres APIs are intended for use in drivers, where the managed lifetime
> of resources is tied directly to the driver attach/detach cycle. In
> shared subsystem code, there is no guarantee that the subsystem
> functions will only be called after a driver has been attached, nor that
> they will not be referenced after the managed resources have been
> released during driver detach.
> 
> To ensure correct lifetime handling, avoid using devres-based
> allocations in the reboot-mode and explicitly handle allocation and
> cleanup of resources.
> 
> Fixes: 4fcd504edbf7 ("power: reset: add reboot mode driver")
> Signed-off-by: Shivendra Pratap <shivendra.pratap@xxxxxxxxxxxxxxxx>
> ---

Reviewed-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>

The patch does not apply, though.

-- Sebastian

>  drivers/power/reset/reboot-mode.c | 33 ++++++++++++++++++++-------------
>  1 file changed, 20 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
> index fba53f638da04655e756b5f8b7d2d666d1379535..d033043f5250a4de152a7786ef37e88a0ace3bbb 100644
> --- a/drivers/power/reset/reboot-mode.c
> +++ b/drivers/power/reset/reboot-mode.c
> @@ -3,13 +3,17 @@
>   * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
>   */
>  
> +#define pr_fmt(fmt)	"reboot-mode: " fmt
> +
>  #include <linux/device.h>
>  #include <linux/init.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> +#include <linux/property.h>
>  #include <linux/reboot.h>
>  #include <linux/reboot-mode.h>
> +#include <linux/slab.h>
>  
>  #define PREFIX "mode-"
>  
> @@ -74,6 +78,7 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
>  	struct property *prop;
>  	struct device_node *np = reboot->dev->of_node;
>  	size_t len = strlen(PREFIX);
> +	u32 magic;
>  	int ret;
>  
>  	INIT_LIST_HEAD(&reboot->head);
> @@ -82,19 +87,18 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
>  		if (strncmp(prop->name, PREFIX, len))
>  			continue;
>  
> -		info = devm_kzalloc(reboot->dev, sizeof(*info), GFP_KERNEL);
> +		if (device_property_read_u32(reboot->dev, prop->name, &magic)) {
> +			pr_debug("reboot mode %s without magic number\n", prop->name);
> +			continue;
> +		}
> +
> +		info = kzalloc(sizeof(*info), GFP_KERNEL);
>  		if (!info) {
>  			ret = -ENOMEM;
>  			goto error;
>  		}
>  
> -		if (of_property_read_u32(np, prop->name, &info->magic)) {
> -			dev_err(reboot->dev, "reboot mode %s without magic number\n",
> -				info->mode);
> -			devm_kfree(reboot->dev, info);
> -			continue;
> -		}
> -
> +		info->magic = magic;
>  		info->mode = kstrdup_const(prop->name + len, GFP_KERNEL);
>  		if (!info->mode) {
>  			ret =  -ENOMEM;
> @@ -102,8 +106,7 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
>  		} else if (info->mode[0] == '\0') {
>  			kfree_const(info->mode);
>  			ret = -EINVAL;
> -			dev_err(reboot->dev, "invalid mode name(%s): too short!\n",
> -				prop->name);
> +			pr_err("invalid mode name(%s): too short!\n", prop->name);
>  			goto error;
>  		}
>  
> @@ -116,8 +119,8 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
>  	return 0;
>  
>  error:
> -	list_for_each_entry(info, &reboot->head, list)
> -		kfree_const(info->mode);
> +	kfree(info);
> +	reboot_mode_unregister(reboot);
>  
>  	return ret;
>  }
> @@ -130,11 +133,15 @@ EXPORT_SYMBOL_GPL(reboot_mode_register);
>  int reboot_mode_unregister(struct reboot_mode_driver *reboot)
>  {
>  	struct mode_info *info;
> +	struct mode_info *next;
>  
>  	unregister_reboot_notifier(&reboot->reboot_notifier);
>  
> -	list_for_each_entry(info, &reboot->head, list)
> +	list_for_each_entry_safe(info, next, &reboot->head, list) {
> +		list_del(&info->list);
>  		kfree_const(info->mode);
> +		kfree(info);
> +	}
>  
>  	return 0;
>  }
> 
> -- 
> 2.34.1
>

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