From b57100a3d9ced8c2b78e87d313f514a3338d016e Mon Sep 17 00:00:00 2001 From: Malaya Kumar Rout Date: Tue, 14 Oct 2025 01:00:27 +0530 Subject: PM: console: Fix memory allocation error handling in pm_vt_switch_required() The pm_vt_switch_required() function fails silently when memory allocation fails, offering no indication to callers that the operation was unsuccessful. This behavior prevents drivers from handling allocation errors correctly or implementing retry mechanisms. By ensuring that failures are reported back to the caller, drivers can make informed decisions, improve robustness, and avoid unexpected behavior during critical power management operations. Change the function signature to return an integer error code and modify the implementation to return -ENOMEM when kmalloc() fails. Update both the function declaration and the inline stub in include/linux/pm.h to maintain consistency across CONFIG_VT_CONSOLE_SLEEP configurations. The function now returns: - 0 on success (including when updating existing entries) - -ENOMEM when memory allocation fails This change improves error reporting without breaking existing callers, as the current callers in drivers/video/fbdev/core/fbmem.c already ignore the return value, making this a backward-compatible improvement. Reviewed-by: Lyude Paul Signed-off-by: Malaya Kumar Rout Reviewed-by: Dhruva Gole Reviewed-by: Lyude Paul Link: https://patch.msgid.link/20251013193028.89570-1-mrout@redhat.com Signed-off-by: Rafael J. Wysocki --- include/linux/pm.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/pm.h b/include/linux/pm.h index cc7b2dc28574..a72e42eec130 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -25,11 +25,12 @@ extern void (*pm_power_off)(void); struct device; /* we have a circular dep with device.h */ #ifdef CONFIG_VT_CONSOLE_SLEEP -extern void pm_vt_switch_required(struct device *dev, bool required); +extern int pm_vt_switch_required(struct device *dev, bool required); extern void pm_vt_switch_unregister(struct device *dev); #else -static inline void pm_vt_switch_required(struct device *dev, bool required) +static inline int pm_vt_switch_required(struct device *dev, bool required) { + return 0; } static inline void pm_vt_switch_unregister(struct device *dev) { -- cgit v1.2.3 From 8e4ec90701efec7f2814c89b398d6d4272636814 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 20 Oct 2025 07:55:55 -1000 Subject: freezer: Clarify that only cgroup1 freezer uses PM freezer cgroup1 freezer piggybacks on the PM freezer, which inadvertently allowed userspace to produce uninterruptible tasks at will. To avoid the issue, cgroup2 freezer switched to a separate job control based mechanism. While this happened a long time ago, the code and comment haven't been updated making it confusing to people who aren't familiar with the history. Rename cgroup_freezing() to cgroup1_freezing() and update comments on top of freezing() and frozen() to clarify that cgroup2 freezer isn't covered by the PM freezer mechanism. Signed-off-by: Tejun Heo Suggested-by: Qu Wenruo Link: https://patch.msgid.link/aPZ3q6Hm865NicBC@slm.duckdns.org Signed-off-by: Rafael J. Wysocki --- include/linux/freezer.h | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/freezer.h b/include/linux/freezer.h index 32884c9721e5..0a8c6c4d1a82 100644 --- a/include/linux/freezer.h +++ b/include/linux/freezer.h @@ -22,14 +22,18 @@ extern bool pm_nosig_freezing; /* PM nosig freezing in effect */ extern unsigned int freeze_timeout_msecs; /* - * Check if a process has been frozen + * Check if a process has been frozen for PM or cgroup1 freezer. Note that + * cgroup2 freezer uses the job control mechanism and does not interact with + * the PM freezer. */ extern bool frozen(struct task_struct *p); extern bool freezing_slow_path(struct task_struct *p); /* - * Check if there is a request to freeze a process + * Check if there is a request to freeze a task from PM or cgroup1 freezer. + * Note that cgroup2 freezer uses the job control mechanism and does not + * interact with the PM freezer. */ static inline bool freezing(struct task_struct *p) { @@ -63,9 +67,9 @@ extern bool freeze_task(struct task_struct *p); extern bool set_freezable(void); #ifdef CONFIG_CGROUP_FREEZER -extern bool cgroup_freezing(struct task_struct *task); +extern bool cgroup1_freezing(struct task_struct *task); #else /* !CONFIG_CGROUP_FREEZER */ -static inline bool cgroup_freezing(struct task_struct *task) +static inline bool cgroup1_freezing(struct task_struct *task) { return false; } -- cgit v1.2.3 From 0ca04993dac9b0d21ffbfd22bf54cc43ec2c49f2 Mon Sep 17 00:00:00 2001 From: "Mario Limonciello (AMD)" Date: Wed, 12 Nov 2025 16:40:23 -0600 Subject: PM: Introduce new PMSG_POWEROFF event PMSG_POWEROFF will be used for the PM core to allow differentiating between a hibernation or shutdown sequence when re-using callbacks for common code. Hibernation is started by writing a hibernation method (such as 'platform' 'shutdown', or 'reboot') to use into /sys/power/disk and writing 'disk' to /sys/power/state. Shutdown is initiated with the reboot() syscall with arguments on whether to halt the system or power it off. Tested-by: Eric Naim Signed-off-by: Mario Limonciello (AMD) Link: https://patch.msgid.link/20251112224025.2051702-2-superm1@kernel.org Signed-off-by: Rafael J. Wysocki --- include/linux/pm.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux') diff --git a/include/linux/pm.h b/include/linux/pm.h index a72e42eec130..7f69f739f613 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -508,6 +508,7 @@ const struct dev_pm_ops name = { \ * RECOVER Creation of a hibernation image or restoration of the main * memory contents from a hibernation image has failed, call * ->thaw() and ->complete() for all devices. + * POWEROFF System will poweroff, call ->poweroff() for all devices. * * The following PM_EVENT_ messages are defined for internal use by * kernel subsystems. They are never issued by the PM core. @@ -538,6 +539,7 @@ const struct dev_pm_ops name = { \ #define PM_EVENT_USER 0x0100 #define PM_EVENT_REMOTE 0x0200 #define PM_EVENT_AUTO 0x0400 +#define PM_EVENT_POWEROFF 0x0800 #define PM_EVENT_SLEEP (PM_EVENT_SUSPEND | PM_EVENT_HIBERNATE) #define PM_EVENT_USER_SUSPEND (PM_EVENT_USER | PM_EVENT_SUSPEND) @@ -552,6 +554,7 @@ const struct dev_pm_ops name = { \ #define PMSG_QUIESCE ((struct pm_message){ .event = PM_EVENT_QUIESCE, }) #define PMSG_SUSPEND ((struct pm_message){ .event = PM_EVENT_SUSPEND, }) #define PMSG_HIBERNATE ((struct pm_message){ .event = PM_EVENT_HIBERNATE, }) +#define PMSG_POWEROFF ((struct pm_message){ .event = PM_EVENT_POWEROFF, }) #define PMSG_RESUME ((struct pm_message){ .event = PM_EVENT_RESUME, }) #define PMSG_THAW ((struct pm_message){ .event = PM_EVENT_THAW, }) #define PMSG_RESTORE ((struct pm_message){ .event = PM_EVENT_RESTORE, }) -- cgit v1.2.3