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@oss.qualcomm.com>
---
drivers/power/reset/reboot-mode.c | 34 ++++++++++++++++++++++------------
1 file changed, 22 insertions(+), 12 deletions(-)
diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
index fba53f638da04655e756b5f8b7d2d666d1379535..3af6bc16a76daee686e8110b74e71b0e62b13ef8 100644
--- a/drivers/power/reset/reboot-mode.c
+++ b/drivers/power/reset/reboot-mode.c
@@ -3,6 +3,8 @@
* 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>
@@ -10,6 +12,7 @@
#include <linux/of.h>
#include <linux/reboot.h>
#include <linux/reboot-mode.h>
+#include <linux/slab.h>
#define PREFIX "mode-"
@@ -71,9 +74,11 @@ static int reboot_mode_notify(struct notifier_block *this,
int reboot_mode_register(struct reboot_mode_driver *reboot)
{
struct mode_info *info;
+ struct mode_info *next;
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 +87,17 @@ 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 (of_property_read_u32(np, prop->name, &magic)) {
+ pr_err("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->mode = kstrdup_const(prop->name + len, GFP_KERNEL);
if (!info->mode) {
ret = -ENOMEM;
@@ -102,8 +105,7 @@ 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 +118,12 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
return 0;
error:
- list_for_each_entry(info, &reboot->head, list)
+ kfree(info);
+ list_for_each_entry_safe(info, next, &reboot->head, list) {
+ list_del(&info->list);
kfree_const(info->mode);
+ kfree(info);
+ }
return ret;
}
@@ -130,11 +136,15 @@ 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;
}
--
2.34.1On Sun, Dec 28, 2025 at 6:20 PM Shivendra Pratap
<shivendra.pratap@oss.qualcomm.com> 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@oss.qualcomm.com>
> ---
> drivers/power/reset/reboot-mode.c | 34 ++++++++++++++++++++++------------
> 1 file changed, 22 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
> index fba53f638da04655e756b5f8b7d2d666d1379535..3af6bc16a76daee686e8110b74e71b0e62b13ef8 100644
> --- a/drivers/power/reset/reboot-mode.c
> +++ b/drivers/power/reset/reboot-mode.c
> @@ -3,6 +3,8 @@
> * 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>
> @@ -10,6 +12,7 @@
> #include <linux/of.h>
> #include <linux/reboot.h>
> #include <linux/reboot-mode.h>
> +#include <linux/slab.h>
>
> #define PREFIX "mode-"
>
> @@ -71,9 +74,11 @@ static int reboot_mode_notify(struct notifier_block *this,
> int reboot_mode_register(struct reboot_mode_driver *reboot)
> {
> struct mode_info *info;
> + struct mode_info *next;
> 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 +87,17 @@ 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 (of_property_read_u32(np, prop->name, &magic)) {
Please use device_property_read_u32() if you have access to a device struct.
> + pr_err("reboot mode %s without magic number\n", prop->name);
If this is an error, shouldn't we bail out?
> + 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->mode = kstrdup_const(prop->name + len, GFP_KERNEL);
> if (!info->mode) {
> ret = -ENOMEM;
> @@ -102,8 +105,7 @@ 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 +118,12 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
> return 0;
>
> error:
> - list_for_each_entry(info, &reboot->head, list)
> + kfree(info);
> + list_for_each_entry_safe(info, next, &reboot->head, list) {
> + list_del(&info->list);
> kfree_const(info->mode);
> + kfree(info);
> + }
>
> return ret;
> }
> @@ -130,11 +136,15 @@ 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);
> + }
The code is repeated here, maybe factor it out into a separate function?
>
> return 0;
> }
>
> --
> 2.34.1
>
Bart
On 1/2/2026 3:35 PM, Bartosz Golaszewski wrote:
> On Sun, Dec 28, 2025 at 6:20 PM Shivendra Pratap
> <shivendra.pratap@oss.qualcomm.com> wrote:
[snip]
>
>> + pr_err("reboot mode %s without magic number\n", prop->name);
>
> If this is an error, shouldn't we bail out?
>
>> + continue;
This is not an error as per original design of reboot-mode framework.
The code as of now says, if the reboot-mode node has an entry without
proper magic value, ignore it, and, process the next.
thanks,
Shivendra
On Mon, Jan 05, 2026 at 11:46:40PM +0530, Shivendra Pratap wrote:
>
>
> On 1/2/2026 3:35 PM, Bartosz Golaszewski wrote:
> > On Sun, Dec 28, 2025 at 6:20 PM Shivendra Pratap
> > <shivendra.pratap@oss.qualcomm.com> wrote:
>
> [snip]
>
> >
> >> + pr_err("reboot mode %s without magic number\n", prop->name);
> >
> > If this is an error, shouldn't we bail out?
> >
> >> + continue;
>
> This is not an error as per original design of reboot-mode framework.
> The code as of now says, if the reboot-mode node has an entry without
> proper magic value, ignore it, and, process the next.
Then why are you using error level for the message printout?
--
With best wishes
Dmitry
On 1/6/2026 3:01 AM, Dmitry Baryshkov wrote:
> On Mon, Jan 05, 2026 at 11:46:40PM +0530, Shivendra Pratap wrote:
>>
>>
>> On 1/2/2026 3:35 PM, Bartosz Golaszewski wrote:
>>> On Sun, Dec 28, 2025 at 6:20 PM Shivendra Pratap
>>> <shivendra.pratap@oss.qualcomm.com> wrote:
>>
>> [snip]
>>
>>>
>>>> + pr_err("reboot mode %s without magic number\n", prop->name);
>>>
>>> If this is an error, shouldn't we bail out?
>>>
>>>> + continue;
>>
>> This is not an error as per original design of reboot-mode framework.
>> The code as of now says, if the reboot-mode node has an entry without
>> proper magic value, ignore it, and, process the next.
>
> Then why are you using error level for the message printout?
I have changed from dev_err to pr_err. Can make it pr_info. Will
that change need a mention in commit text?
thanks,
Shivendra
On Tue, Jan 6, 2026 at 7:31 AM Shivendra Pratap
<shivendra.pratap@oss.qualcomm.com> wrote:
>
>
>
> On 1/6/2026 3:01 AM, Dmitry Baryshkov wrote:
> > On Mon, Jan 05, 2026 at 11:46:40PM +0530, Shivendra Pratap wrote:
> >>
> >>
> >> On 1/2/2026 3:35 PM, Bartosz Golaszewski wrote:
> >>> On Sun, Dec 28, 2025 at 6:20 PM Shivendra Pratap
> >>> <shivendra.pratap@oss.qualcomm.com> wrote:
> >>
> >> [snip]
> >>
> >>>
> >>>> + pr_err("reboot mode %s without magic number\n", prop->name);
> >>>
> >>> If this is an error, shouldn't we bail out?
> >>>
> >>>> + continue;
> >>
> >> This is not an error as per original design of reboot-mode framework.
> >> The code as of now says, if the reboot-mode node has an entry without
> >> proper magic value, ignore it, and, process the next.
> >
> > Then why are you using error level for the message printout?
>
> I have changed from dev_err to pr_err. Can make it pr_info. Will
> that change need a mention in commit text?
>
If we can ignore something safely, then I'd just use pr_debug().
Bart
On 1/6/2026 6:00 PM, Bartosz Golaszewski wrote:
> On Tue, Jan 6, 2026 at 7:31 AM Shivendra Pratap
> <shivendra.pratap@oss.qualcomm.com> wrote:
>>
>>
>>
>> On 1/6/2026 3:01 AM, Dmitry Baryshkov wrote:
>>> On Mon, Jan 05, 2026 at 11:46:40PM +0530, Shivendra Pratap wrote:
>>>>
>>>>
>>>> On 1/2/2026 3:35 PM, Bartosz Golaszewski wrote:
>>>>> On Sun, Dec 28, 2025 at 6:20 PM Shivendra Pratap
>>>>> <shivendra.pratap@oss.qualcomm.com> wrote:
>>>>
>>>> [snip]
>>>>
>>>>>
>>>>>> + pr_err("reboot mode %s without magic number\n", prop->name);
>>>>>
>>>>> If this is an error, shouldn't we bail out?
>>>>>
>>>>>> + continue;
>>>>
>>>> This is not an error as per original design of reboot-mode framework.
>>>> The code as of now says, if the reboot-mode node has an entry without
>>>> proper magic value, ignore it, and, process the next.
>>>
>>> Then why are you using error level for the message printout?
>>
>> I have changed from dev_err to pr_err. Can make it pr_info. Will
>> that change need a mention in commit text?
>>
>
> If we can ignore something safely, then I'd just use pr_debug().
Ack.
thanks,
Shivendra
On 1/2/2026 3:35 PM, Bartosz Golaszewski wrote:
> On Sun, Dec 28, 2025 at 6:20 PM Shivendra Pratap
> <shivendra.pratap@oss.qualcomm.com> 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.
[SNIP..]
>>
>> @@ -71,9 +74,11 @@ static int reboot_mode_notify(struct notifier_block *this,
>> int reboot_mode_register(struct reboot_mode_driver *reboot)
>> {
>> struct mode_info *info;
>> + struct mode_info *next;
>> 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 +87,17 @@ 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 (of_property_read_u32(np, prop->name, &magic)) {
>
> Please use device_property_read_u32() if you have access to a device struct.
Ack. Can it go in same patch with the fixes tag?
>
>> + pr_err("reboot mode %s without magic number\n", prop->name);
>
> If this is an error, shouldn't we bail out?
>
>> + 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->mode = kstrdup_const(prop->name + len, GFP_KERNEL);
>> if (!info->mode) {
>> ret = -ENOMEM;
>> @@ -102,8 +105,7 @@ 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 +118,12 @@ int reboot_mode_register(struct reboot_mode_driver *reboot)
>> return 0;
>>
>> error:
>> - list_for_each_entry(info, &reboot->head, list)
>> + kfree(info);
>> + list_for_each_entry_safe(info, next, &reboot->head, list) {
>> + list_del(&info->list);
>> kfree_const(info->mode);
>> + kfree(info);
>> + }
>>
>> return ret;
>> }
>> @@ -130,11 +136,15 @@ 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);
>> + }
>
> The code is repeated here, maybe factor it out into a separate function?
Ack. let me try that.
thanks,
Shivendra
On Mon, Jan 5, 2026 at 6:54 PM Shivendra Pratap
<shivendra.pratap@oss.qualcomm.com> wrote:
>
> >>
> >> INIT_LIST_HEAD(&reboot->head);
> >> @@ -82,19 +87,17 @@ 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 (of_property_read_u32(np, prop->name, &magic)) {
> >
> > Please use device_property_read_u32() if you have access to a device struct.
>
> Ack. Can it go in same patch with the fixes tag?
>
I would be fine with it but it's more a question to Sebastian as the maintainer.
Bart
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