[PATCH v14 01/10] power: reset: reboot-mode: Synchronize list traversal
From: Shivendra Pratap <hidden>
Date: 2025-08-15 14:36:39
Also in:
linux-arm-msm, linux-devicetree, linux-pm, lkml
Subsystem:
system reset/shutdown drivers, the rest · Maintainers:
Sebastian Reichel, Linus Torvalds
List traversals must be synchronized to prevent race conditions and data corruption. The reboot-mode list is not protected by a lock currently, which can lead to concurrent access and race. Introduce a mutex lock to guard all operations on the reboot-mode list and ensure thread-safe access. The change prevents unsafe concurrent access on reboot-mode list. Signed-off-by: Shivendra Pratap <redacted> --- drivers/power/reset/reboot-mode.c | 24 ++++++++++++++++++++---- include/linux/reboot-mode.h | 4 ++++ 2 files changed, 24 insertions(+), 4 deletions(-)
diff --git a/drivers/power/reset/reboot-mode.c b/drivers/power/reset/reboot-mode.c
index fba53f638da04655e756b5f8b7d2d666d1379535..42bb99128ed3846d4bff62416dc31135ddeaeb90 100644
--- a/drivers/power/reset/reboot-mode.c
+++ b/drivers/power/reset/reboot-mode.c@@ -29,9 +29,14 @@ static unsigned int get_reboot_mode_magic(struct reboot_mode_driver *reboot, if (!cmd) cmd = normal; - list_for_each_entry(info, &reboot->head, list) - if (!strcmp(info->mode, cmd)) + mutex_lock(&reboot->rb_lock); + list_for_each_entry(info, &reboot->head, list) { + if (!strcmp(info->mode, cmd)) { + mutex_unlock(&reboot->rb_lock); return info->magic; + } + } + mutex_unlock(&reboot->rb_lock); /* try to match again, replacing characters impossible in DT */ if (strscpy(cmd_, cmd, sizeof(cmd_)) == -E2BIG)
@@ -41,9 +46,14 @@ static unsigned int get_reboot_mode_magic(struct reboot_mode_driver *reboot, strreplace(cmd_, ',', '-'); strreplace(cmd_, '/', '-'); - list_for_each_entry(info, &reboot->head, list) - if (!strcmp(info->mode, cmd_)) + mutex_lock(&reboot->rb_lock); + list_for_each_entry(info, &reboot->head, list) { + if (!strcmp(info->mode, cmd_)) { + mutex_unlock(&reboot->rb_lock); return info->magic; + } + } + mutex_unlock(&reboot->rb_lock); return 0; }
@@ -77,7 +87,9 @@ int reboot_mode_register(struct reboot_mode_driver *reboot) int ret; INIT_LIST_HEAD(&reboot->head); + mutex_init(&reboot->rb_lock); + mutex_lock(&reboot->rb_lock); for_each_property_of_node(np, prop) { if (strncmp(prop->name, PREFIX, len)) continue;
@@ -113,12 +125,14 @@ int reboot_mode_register(struct reboot_mode_driver *reboot) reboot->reboot_notifier.notifier_call = reboot_mode_notify; register_reboot_notifier(&reboot->reboot_notifier); + mutex_unlock(&reboot->rb_lock); return 0; error: list_for_each_entry(info, &reboot->head, list) kfree_const(info->mode); + mutex_unlock(&reboot->rb_lock); return ret; } EXPORT_SYMBOL_GPL(reboot_mode_register);
@@ -133,8 +147,10 @@ int reboot_mode_unregister(struct reboot_mode_driver *reboot) unregister_reboot_notifier(&reboot->reboot_notifier); + mutex_lock(&reboot->rb_lock); list_for_each_entry(info, &reboot->head, list) kfree_const(info->mode); + mutex_unlock(&reboot->rb_lock); return 0; }
diff --git a/include/linux/reboot-mode.h b/include/linux/reboot-mode.h
index 4a2abb38d1d612ec0fdf05eb18c98b210f631b7f..b73f80708197677db8dc2e43affc519782b7146e 100644
--- a/include/linux/reboot-mode.h
+++ b/include/linux/reboot-mode.h@@ -2,11 +2,15 @@ #ifndef __REBOOT_MODE_H__ #define __REBOOT_MODE_H__ +#include <linux/mutex.h> + struct reboot_mode_driver { struct device *dev; struct list_head head; int (*write)(struct reboot_mode_driver *reboot, unsigned int magic); struct notifier_block reboot_notifier; + /*Protects access to reboot mode list*/ + struct mutex rb_lock; }; int reboot_mode_register(struct reboot_mode_driver *reboot);
--
2.34.1