Merge tag 'pm-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "There are quite a few interesting things here, including new hardware
  support, new features, some bug fixes and documentation updates. In
  addition, there are a usual bunch of minor fixes and cleanups all
  over.

  In the new hardware support category, there are intel_pstate and
  intel_rapl driver updates to support new processors, Panther Lake,
  Wildcat Lake, Noval Lake, and Diamond Rapids in the OOB mode, OPP and
  bandwidth allocation support in the tegra186 cpufreq driver, and
  JH7110S SOC support in dt-platdev cpufreq.

  The new features are the PM QoS CPU latency limit for suspend-to-idle,
  the netlink support for the energy model management, support for
  terminating system suspend via a wakeup event during the sync of file
  systems, configurable number of hibernation compression threads, the
  runtime PM auto-cleanup macros, and the "poweroff" PM event that is
  expected to be used during system shutdown.

  Bugs are mostly fixed in cpuidle governors, but there are also fixes
  elsewhere, like in the amd-pstate cpufreq driver.

  Documentation updates include, but are not limited to, a new doc on
  debugging shutdown hangs, cross-referencing fixes and cleanups in the
  intel_pstate documentation, and updates of comments in the core
  hibernation code.

  Specifics:

   - Introduce and document a QoS limit on CPU exit latency during
     wakeup from suspend-to-idle (Ulf Hansson)

   - Add support for building libcpupower statically (Zuo An)

   - Add support for sending netlink notifications to user space on
     energy model updates (Changwoo Mini, Peng Fan)

   - Minor improvements to the Rust OPP interface (Tamir Duberstein)

   - Fixes to scope-based pointers in the OPP library (Viresh Kumar)

   - Use residency threshold in polling state override decisions in the
     menu cpuidle governor (Aboorva Devarajan)

   - Add sanity check for exit latency and target residency in the
     cpufreq core (Rafael Wysocki)

   - Use this_cpu_ptr() where possible in the teo governor (Christian
     Loehle)

   - Rework the handling of tick wakeups in the teo cpuidle governor to
     increase the likelihood of stopping the scheduler tick in the cases
     when tick wakeups can be counted as non-timer ones (Rafael Wysocki)

   - Fix a reverse condition in the teo cpuidle governor and drop a
     misguided target residency check from it (Rafael Wysocki)

   - Clean up multiple minor defects in the teo cpuidle governor (Rafael
     Wysocki)

   - Update header inclusion to make it follow the Include What You Use
     principle (Andy Shevchenko)

   - Enable MSR-based RAPL PMU support in the intel_rapl power capping
     driver and arrange for using it on the Panther Lake and Wildcat
     Lake processors (Kuppuswamy Sathyanarayanan)

   - Add support for Nova Lake and Wildcat Lake processors to the
     intel_rapl power capping driver (Kaushlendra Kumar, Srinivas
     Pandruvada)

   - Add OPP and bandwidth support for Tegra186 (Aaron Kling)

   - Optimizations for parameter array handling in the amd-pstate
     cpufreq driver (Mario Limonciello)

   - Fix for mode changes with offline CPUs in the amd-pstate cpufreq
     driver (Gautham Shenoy)

   - Preserve freq_table_sorted across suspend/hibernate in the cpufreq
     core (Zihuan Zhang)

   - Adjust energy model rules for Intel hybrid platforms in the
     intel_pstate cpufreq driver and improve printing of debug messages
     in it (Rafael Wysocki)

   - Replace deprecated strcpy() in cpufreq_unregister_governor()
     (Thorsten Blum)

   - Fix duplicate hyperlink target errors in the intel_pstate cpufreq
     driver documentation and use :ref: directive for internal linking
     in it (Swaraj Gaikwad, Bagas Sanjaya)

   - Add Diamond Rapids OOB mode support to the intel_pstate cpufreq
     driver (Kuppuswamy Sathyanarayanan)

   - Use mutex guard for driver locking in the intel_pstate driver and
     eliminate some code duplication from it (Rafael Wysocki)

   - Replace udelay() with usleep_range() in ACPI cpufreq (Kaushlendra
     Kumar)

   - Minor improvements to various cpufreq drivers (Christian Marangi,
     Hal Feng, Jie Zhan, Marco Crivellari, Miaoqian Lin, and Shuhao Fu)

   - Replace snprintf() with scnprintf() in show_trace_dev_match()
     (Kaushlendra Kumar)

   - Fix memory allocation error handling in pm_vt_switch_required()
     (Malaya Kumar Rout)

   - Introduce CALL_PM_OP() macro and use it to simplify code in generic
     PM operations (Kaushlendra Kumar)

   - Add module param to backtrace all CPUs in the device power
     management watchdog (Sergey Senozhatsky)

   - Rework message printing in swsusp_save() (Rafael Wysocki)

   - Make it possible to change the number of hibernation compression
     threads (Xueqin Luo)

   - Clarify that only cgroup1 freezer uses PM freezer (Tejun Heo)

   - Add document on debugging shutdown hangs to PM documentation and
     correct a mistaken configuration option in it (Mario Limonciello)

   - Shut down wakeup source timer before removing the wakeup source
     from the list (Kaushlendra Kumar, Rafael Wysocki)

   - Introduce new PMSG_POWEROFF event for system shutdown handling with
     the help of PM device callbacks (Mario Limonciello)

   - Make pm_test delay interruptible by wakeup events (Riwen Lu)

   - Clean up kernel-doc comment style usage in the core hibernation
     code and remove unuseful comments from it (Sunday Adelodun, Rafael
     Wysocki)

   - Add support for handling wakeup events and aborting the suspend
     process while it is syncing file systems (Samuel Wu, Rafael
     Wysocki)

   - Add WQ_UNBOUND to pm_wq workqueue (Marco Crivellari)

   - Add runtime PM wrapper macros for ACQUIRE()/ACQUIRE_ERR() and use
     them in the PCI core and the ACPI TAD driver (Rafael Wysocki)

   - Improve runtime PM in the ACPI TAD driver (Rafael Wysocki)

   - Update pm_runtime_allow/forbid() documentation (Rafael Wysocki)

   - Fix typos in runtime.c comments (Malaya Kumar Rout)

   - Move governor.h from devfreq under include/linux/ and rename to
     devfreq-governor.h to allow devfreq governor definitions in out of
     drivers/devfreq/ (Dmitry Baryshkov)

   - Use min() to improve readability in tegra30-devfreq.c (Thorsten
     Blum)

   - Fix potential use-after-free issue of OPP handling in
     hisi_uncore_freq.c (Pengjie Zhang)

   - Fix typo in DFSO_DOWNDIFFERENTIAL macro name in
     governor_simpleondemand.c in devfreq (Riwen Lu)"

* tag 'pm-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (96 commits)
  PM / devfreq: Fix typo in DFSO_DOWNDIFFERENTIAL macro name
  cpuidle: Warn instead of bailing out if target residency check fails
  cpuidle: Update header inclusion
  Documentation: power/cpuidle: Document the CPU system wakeup latency QoS
  cpuidle: Respect the CPU system wakeup QoS limit for cpuidle
  sched: idle: Respect the CPU system wakeup QoS limit for s2idle
  pmdomain: Respect the CPU system wakeup QoS limit for cpuidle
  pmdomain: Respect the CPU system wakeup QoS limit for s2idle
  PM: QoS: Introduce a CPU system wakeup QoS limit
  cpuidle: governors: teo: Add missing space to the description
  PM: hibernate: Extra cleanup of comments in swap handling code
  PM / devfreq: tegra30: use min to simplify actmon_cpu_to_emc_rate
  PM / devfreq: hisi: Fix potential UAF in OPP handling
  PM / devfreq: Move governor.h to a public header location
  powercap: intel_rapl: Enable MSR-based RAPL PMU support
  powercap: intel_rapl: Prepare read_raw() interface for atomic-context callers
  cpufreq: qcom-nvmem: fix compilation warning for qcom_cpufreq_ipq806x_match_list
  PM: sleep: Call pm_sleep_fs_sync() instead of ksys_sync_helper()
  PM: sleep: Add support for wakeup during filesystem sync
  cpufreq: ACPI: Replace udelay() with usleep_range()
  ...

5 files changed, 68 insertions, 83 deletions

diff --git a/drivers/base/power/generic_ops.c b/drivers/base/power/generic_ops.c
index 6502720bb564..af99bbcf281c 100644
--- a/drivers/base/power/generic_ops.c
+++ b/drivers/base/power/generic_ops.c
@@ -8,6 +8,13 @@
 #include <linux/pm_runtime.h>
 #include <linux/export.h>
 
+#define CALL_PM_OP(dev, op) \
+({ \
+	struct device *_dev = (dev); \
+	const struct dev_pm_ops *pm = _dev->driver ? _dev->driver->pm : NULL; \
+	pm && pm->op ? pm->op(_dev) : 0; \
+})
+
 #ifdef CONFIG_PM
 /**
  * pm_generic_runtime_suspend - Generic runtime suspend callback for subsystems.
@@ -19,12 +26,7 @@
  */
 int pm_generic_runtime_suspend(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-	int ret;
-
-	ret = pm && pm->runtime_suspend ? pm->runtime_suspend(dev) : 0;
-
-	return ret;
+	return CALL_PM_OP(dev, runtime_suspend);
 }
 EXPORT_SYMBOL_GPL(pm_generic_runtime_suspend);
 
@@ -38,12 +40,7 @@ EXPORT_SYMBOL_GPL(pm_generic_runtime_suspend);
  */
 int pm_generic_runtime_resume(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-	int ret;
-
-	ret = pm && pm->runtime_resume ? pm->runtime_resume(dev) : 0;
-
-	return ret;
+	return CALL_PM_OP(dev, runtime_resume);
 }
 EXPORT_SYMBOL_GPL(pm_generic_runtime_resume);
 #endif /* CONFIG_PM */
@@ -72,9 +69,7 @@ int pm_generic_prepare(struct device *dev)
  */
 int pm_generic_suspend_noirq(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->suspend_noirq ? pm->suspend_noirq(dev) : 0;
+	return CALL_PM_OP(dev, suspend_noirq);
 }
 EXPORT_SYMBOL_GPL(pm_generic_suspend_noirq);
 
@@ -84,9 +79,7 @@ EXPORT_SYMBOL_GPL(pm_generic_suspend_noirq);
  */
 int pm_generic_suspend_late(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->suspend_late ? pm->suspend_late(dev) : 0;
+	return CALL_PM_OP(dev, suspend_late);
 }
 EXPORT_SYMBOL_GPL(pm_generic_suspend_late);
 
@@ -96,9 +89,7 @@ EXPORT_SYMBOL_GPL(pm_generic_suspend_late);
  */
 int pm_generic_suspend(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->suspend ? pm->suspend(dev) : 0;
+	return CALL_PM_OP(dev, suspend);
 }
 EXPORT_SYMBOL_GPL(pm_generic_suspend);
 
@@ -108,9 +99,7 @@ EXPORT_SYMBOL_GPL(pm_generic_suspend);
  */
 int pm_generic_freeze_noirq(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->freeze_noirq ? pm->freeze_noirq(dev) : 0;
+	return CALL_PM_OP(dev, freeze_noirq);
 }
 EXPORT_SYMBOL_GPL(pm_generic_freeze_noirq);
 
@@ -120,9 +109,7 @@ EXPORT_SYMBOL_GPL(pm_generic_freeze_noirq);
  */
 int pm_generic_freeze(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->freeze ? pm->freeze(dev) : 0;
+	return CALL_PM_OP(dev, freeze);
 }
 EXPORT_SYMBOL_GPL(pm_generic_freeze);
 
@@ -132,9 +119,7 @@ EXPORT_SYMBOL_GPL(pm_generic_freeze);
  */
 int pm_generic_poweroff_noirq(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->poweroff_noirq ? pm->poweroff_noirq(dev) : 0;
+	return CALL_PM_OP(dev, poweroff_noirq);
 }
 EXPORT_SYMBOL_GPL(pm_generic_poweroff_noirq);
 
@@ -144,9 +129,7 @@ EXPORT_SYMBOL_GPL(pm_generic_poweroff_noirq);
  */
 int pm_generic_poweroff_late(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->poweroff_late ? pm->poweroff_late(dev) : 0;
+	return CALL_PM_OP(dev, poweroff_late);
 }
 EXPORT_SYMBOL_GPL(pm_generic_poweroff_late);
 
@@ -156,9 +139,7 @@ EXPORT_SYMBOL_GPL(pm_generic_poweroff_late);
  */
 int pm_generic_poweroff(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->poweroff ? pm->poweroff(dev) : 0;
+	return CALL_PM_OP(dev, poweroff);
 }
 EXPORT_SYMBOL_GPL(pm_generic_poweroff);
 
@@ -168,9 +149,7 @@ EXPORT_SYMBOL_GPL(pm_generic_poweroff);
  */
 int pm_generic_thaw_noirq(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->thaw_noirq ? pm->thaw_noirq(dev) : 0;
+	return CALL_PM_OP(dev, thaw_noirq);
 }
 EXPORT_SYMBOL_GPL(pm_generic_thaw_noirq);
 
@@ -180,9 +159,7 @@ EXPORT_SYMBOL_GPL(pm_generic_thaw_noirq);
  */
 int pm_generic_thaw(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->thaw ? pm->thaw(dev) : 0;
+	return CALL_PM_OP(dev, thaw);
 }
 EXPORT_SYMBOL_GPL(pm_generic_thaw);
 
@@ -192,9 +169,7 @@ EXPORT_SYMBOL_GPL(pm_generic_thaw);
  */
 int pm_generic_resume_noirq(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->resume_noirq ? pm->resume_noirq(dev) : 0;
+	return CALL_PM_OP(dev, resume_noirq);
 }
 EXPORT_SYMBOL_GPL(pm_generic_resume_noirq);
 
@@ -204,9 +179,7 @@ EXPORT_SYMBOL_GPL(pm_generic_resume_noirq);
  */
 int pm_generic_resume_early(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->resume_early ? pm->resume_early(dev) : 0;
+	return CALL_PM_OP(dev, resume_early);
 }
 EXPORT_SYMBOL_GPL(pm_generic_resume_early);
 
@@ -216,9 +189,7 @@ EXPORT_SYMBOL_GPL(pm_generic_resume_early);
  */
 int pm_generic_resume(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->resume ? pm->resume(dev) : 0;
+	return CALL_PM_OP(dev, resume);
 }
 EXPORT_SYMBOL_GPL(pm_generic_resume);
 
@@ -228,9 +199,7 @@ EXPORT_SYMBOL_GPL(pm_generic_resume);
  */
 int pm_generic_restore_noirq(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->restore_noirq ? pm->restore_noirq(dev) : 0;
+	return CALL_PM_OP(dev, restore_noirq);
 }
 EXPORT_SYMBOL_GPL(pm_generic_restore_noirq);
 
@@ -240,9 +209,7 @@ EXPORT_SYMBOL_GPL(pm_generic_restore_noirq);
  */
 int pm_generic_restore_early(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->restore_early ? pm->restore_early(dev) : 0;
+	return CALL_PM_OP(dev, restore_early);
 }
 EXPORT_SYMBOL_GPL(pm_generic_restore_early);
 
@@ -252,9 +219,7 @@ EXPORT_SYMBOL_GPL(pm_generic_restore_early);
  */
 int pm_generic_restore(struct device *dev)
 {
-	const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
-
-	return pm && pm->restore ? pm->restore(dev) : 0;
+	return CALL_PM_OP(dev, restore);
 }
 EXPORT_SYMBOL_GPL(pm_generic_restore);
 
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 1de1cd72b616..a0225a83f50c 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -34,6 +34,7 @@
 #include <linux/cpufreq.h>
 #include <linux/devfreq.h>
 #include <linux/timer.h>
+#include <linux/nmi.h>
 
 #include "../base.h"
 #include "power.h"
@@ -95,6 +96,8 @@ static const char *pm_verb(int event)
 		return "restore";
 	case PM_EVENT_RECOVER:
 		return "recover";
+	case PM_EVENT_POWEROFF:
+		return "poweroff";
 	default:
 		return "(unknown PM event)";
 	}
@@ -367,6 +370,7 @@ static pm_callback_t pm_op(const struct dev_pm_ops *ops, pm_message_t state)
 	case PM_EVENT_FREEZE:
 	case PM_EVENT_QUIESCE:
 		return ops->freeze;
+	case PM_EVENT_POWEROFF:
 	case PM_EVENT_HIBERNATE:
 		return ops->poweroff;
 	case PM_EVENT_THAW:
@@ -401,6 +405,7 @@ static pm_callback_t pm_late_early_op(const struct dev_pm_ops *ops,
 	case PM_EVENT_FREEZE:
 	case PM_EVENT_QUIESCE:
 		return ops->freeze_late;
+	case PM_EVENT_POWEROFF:
 	case PM_EVENT_HIBERNATE:
 		return ops->poweroff_late;
 	case PM_EVENT_THAW:
@@ -435,6 +440,7 @@ static pm_callback_t pm_noirq_op(const struct dev_pm_ops *ops, pm_message_t stat
 	case PM_EVENT_FREEZE:
 	case PM_EVENT_QUIESCE:
 		return ops->freeze_noirq;
+	case PM_EVENT_POWEROFF:
 	case PM_EVENT_HIBERNATE:
 		return ops->poweroff_noirq;
 	case PM_EVENT_THAW:
@@ -515,6 +521,11 @@ struct dpm_watchdog {
 #define DECLARE_DPM_WATCHDOG_ON_STACK(wd) \
 	struct dpm_watchdog wd
 
+static bool __read_mostly dpm_watchdog_all_cpu_backtrace;
+module_param(dpm_watchdog_all_cpu_backtrace, bool, 0644);
+MODULE_PARM_DESC(dpm_watchdog_all_cpu_backtrace,
+		 "Backtrace all CPUs on DPM watchdog timeout");
+
 /**
  * dpm_watchdog_handler - Driver suspend / resume watchdog handler.
  * @t: The timer that PM watchdog depends on.
@@ -530,8 +541,12 @@ static void dpm_watchdog_handler(struct timer_list *t)
 	unsigned int time_left;
 
 	if (wd->fatal) {
+		unsigned int this_cpu = smp_processor_id();
+
 		dev_emerg(wd->dev, "**** DPM device timeout ****\n");
 		show_stack(wd->tsk, NULL, KERN_EMERG);
+		if (dpm_watchdog_all_cpu_backtrace)
+			trigger_allbutcpu_cpu_backtrace(this_cpu);
 		panic("%s %s: unrecoverable failure\n",
 			dev_driver_string(wd->dev), dev_name(wd->dev));
 	}
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 1b11a3cd4acc..62707738caa4 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -90,7 +90,7 @@ static void update_pm_runtime_accounting(struct device *dev)
 	/*
 	 * Because ktime_get_mono_fast_ns() is not monotonic during
 	 * timekeeping updates, ensure that 'now' is after the last saved
-	 * timesptamp.
+	 * timestamp.
 	 */
 	if (now < last)
 		return;
@@ -217,7 +217,7 @@ static int dev_memalloc_noio(struct device *dev, void *data)
  *     resume/suspend callback of any one of its ancestors(or the
  *     block device itself), the deadlock may be triggered inside the
  *     memory allocation since it might not complete until the block
- *     device becomes active and the involed page I/O finishes. The
+ *     device becomes active and the involved page I/O finishes. The
  *     situation is pointed out first by Alan Stern. Network device
  *     are involved in iSCSI kind of situation.
  *
@@ -1210,7 +1210,7 @@ EXPORT_SYMBOL_GPL(__pm_runtime_resume);
  *
  * Otherwise, if its runtime PM status is %RPM_ACTIVE and (1) @ign_usage_count
  * is set, or (2) @dev is not ignoring children and its active child count is
- * nonero, or (3) the runtime PM usage counter of @dev is not zero, increment
+ * nonzero, or (3) the runtime PM usage counter of @dev is not zero, increment
  * the usage counter of @dev and return 1.
  *
  * Otherwise, return 0 without changing the usage counter.
@@ -1664,9 +1664,12 @@ EXPORT_SYMBOL_GPL(devm_pm_runtime_get_noresume);
  * pm_runtime_forbid - Block runtime PM of a device.
  * @dev: Device to handle.
  *
- * Increase the device's usage count and clear its power.runtime_auto flag,
- * so that it cannot be suspended at run time until pm_runtime_allow() is called
- * for it.
+ * Resume @dev if already suspended and block runtime suspend of @dev in such
+ * a way that it can be unblocked via the /sys/devices/.../power/control
+ * interface, or otherwise by calling pm_runtime_allow().
+ *
+ * Calling this function many times in a row has the same effect as calling it
+ * once.
  */
 void pm_runtime_forbid(struct device *dev)
 {
@@ -1687,7 +1690,13 @@ EXPORT_SYMBOL_GPL(pm_runtime_forbid);
  * pm_runtime_allow - Unblock runtime PM of a device.
  * @dev: Device to handle.
  *
- * Decrease the device's usage count and set its power.runtime_auto flag.
+ * Unblock runtime suspend of @dev after it has been blocked by
+ * pm_runtime_forbid() (for instance, if it has been blocked via the
+ * /sys/devices/.../power/control interface), check if @dev can be
+ * suspended and suspend it in that case.
+ *
+ * Calling this function many times in a row has the same effect as calling it
+ * once.
  */
 void pm_runtime_allow(struct device *dev)
 {
diff --git a/drivers/base/power/trace.c b/drivers/base/power/trace.c
index cd6e559648b2..d8da7195bb00 100644
--- a/drivers/base/power/trace.c
+++ b/drivers/base/power/trace.c
@@ -238,10 +238,8 @@ int show_trace_dev_match(char *buf, size_t size)
 		unsigned int hash = hash_string(DEVSEED, dev_name(dev),
 						DEVHASH);
 		if (hash == value) {
-			int len = snprintf(buf, size, "%s\n",
+			int len = scnprintf(buf, size, "%s\n",
 					    dev_driver_string(dev));
-			if (len > size)
-				len = size;
 			buf += len;
 			ret += len;
 			size -= len;
diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index d1283ff1080b..1e1a0e7eeac5 100644
--- a/drivers/base/power/wakeup.c
+++ b/drivers/base/power/wakeup.c
@@ -189,17 +189,16 @@ static void wakeup_source_remove(struct wakeup_source *ws)
 	if (WARN_ON(!ws))
 		return;
 
+	/*
+	 * After shutting down the timer, wakeup_source_activate() will warn if
+	 * the given wakeup source is passed to it.
+	 */
+	timer_shutdown_sync(&ws->timer);
+
 	raw_spin_lock_irqsave(&events_lock, flags);
 	list_del_rcu(&ws->entry);
 	raw_spin_unlock_irqrestore(&events_lock, flags);
 	synchronize_srcu(&wakeup_srcu);
-
-	timer_delete_sync(&ws->timer);
-	/*
-	 * Clear timer.function to make wakeup_source_not_registered() treat
-	 * this wakeup source as not registered.
-	 */
-	ws->timer.function = NULL;
 }
 
 /**
@@ -506,14 +505,14 @@ int device_set_wakeup_enable(struct device *dev, bool enable)
 EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
 
 /**
- * wakeup_source_not_registered - validate the given wakeup source.
+ * wakeup_source_not_usable - validate the given wakeup source.
  * @ws: Wakeup source to be validated.
  */
-static bool wakeup_source_not_registered(struct wakeup_source *ws)
+static bool wakeup_source_not_usable(struct wakeup_source *ws)
 {
 	/*
-	 * Use timer struct to check if the given source is initialized
-	 * by wakeup_source_add.
+	 * Use the timer struct to check if the given wakeup source has been
+	 * initialized by wakeup_source_add() and it is not going away.
 	 */
 	return ws->timer.function != pm_wakeup_timer_fn;
 }
@@ -558,8 +557,7 @@ static void wakeup_source_activate(struct wakeup_source *ws)
 {
 	unsigned int cec;
 
-	if (WARN_ONCE(wakeup_source_not_registered(ws),
-			"unregistered wakeup source\n"))
+	if (WARN_ONCE(wakeup_source_not_usable(ws), "unusable wakeup source\n"))
 		return;
 
 	ws->active = true;