[PATCH v3 0/5] rv: LTL per-cpu monitor type and real-time scheduling monitor

[PATCH v3 0/5] rv: LTL per-cpu monitor type and real-time scheduling monitor

[Nam Cao]

Hi,

This series adds support for linear temporal logic per-cpu monitor type,
analogous to deterministic automaton per-cpu monitor. Then a new per-cpu
monitor is added which validates real-time scheduling.

Nam Cao (5):
  rv/ltl: Prepare for other monitor types
  rv/ltl: Support per-cpu monitors
  verification/rvgen/ltl: Support per-cpu monitor generation
  sched: Add task enqueue/dequeue trace points
  rv: Add rts monitor

 Documentation/trace/rv/monitor_rtapp.rst      |  19 +++
 include/linux/rv.h                            |   4 +
 include/rv/ltl_monitor.h                      | 115 +++++++++-----
 include/trace/events/sched.h                  |  13 ++
 kernel/sched/core.c                           |   8 +-
 kernel/trace/rv/Kconfig                       |   5 +
 kernel/trace/rv/Makefile                      |   1 +
 .../trace/rv/monitors/pagefault/pagefault.h   |   2 +
 kernel/trace/rv/monitors/rts/Kconfig          |  17 +++
 kernel/trace/rv/monitors/rts/rts.c            | 144 ++++++++++++++++++
 kernel/trace/rv/monitors/rts/rts.h            | 126 +++++++++++++++
 kernel/trace/rv/monitors/rts/rts_trace.h      |  15 ++
 kernel/trace/rv/monitors/sleep/sleep.h        |   2 +
 kernel/trace/rv/rv_trace.h                    |  47 ++++++
 tools/verification/models/rtapp/rts.ltl       |   5 +
 tools/verification/rvgen/rvgen/ltl2k.py       |  48 +++++-
 .../rvgen/rvgen/templates/ltl2k/main.c        |   9 +-
 .../rvgen/rvgen/templates/ltl2k/trace.h       |   7 +-
 18 files changed, 538 insertions(+), 49 deletions(-)
 create mode 100644 kernel/trace/rv/monitors/rts/Kconfig
 create mode 100644 kernel/trace/rv/monitors/rts/rts.c
 create mode 100644 kernel/trace/rv/monitors/rts/rts.h
 create mode 100644 kernel/trace/rv/monitors/rts/rts_trace.h
 create mode 100644 tools/verification/models/rtapp/rts.ltl

-- 
2.39.5

[PATCH v3 1/5] rv/ltl: Prepare for other monitor types

[Nam Cao]

rv/ltl_monitor.h is the template file used by all LTL monitors. But only
per-task monitor is supported.

Prepare to support for other monitor types:

  - Change the monitored target type into an opaque type which will be
    defined differently depending on the monitor type. This type is only
    defined as struct task_struct * for now.

  - Separate out the per-task-specific printf format and arguments, so that
    rv_cond_react() can be shared with other monitor types.

No functional change intended.

Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Nam Cao <namcao@linutronix.de>
---
v2: define the macros for DA usage as well
---
 include/linux/rv.h                            |  4 +
 include/rv/ltl_monitor.h                      | 85 +++++++++++--------
 .../trace/rv/monitors/pagefault/pagefault.h   |  2 +
 kernel/trace/rv/monitors/sleep/sleep.h        |  2 +
 4 files changed, 58 insertions(+), 35 deletions(-)

diff --git a/include/linux/rv.h b/include/linux/rv.h
index 14410a42faef..10a8be730d89 100644
--- a/include/linux/rv.h
+++ b/include/linux/rv.h
@@ -13,6 +13,10 @@
 #define MAX_DA_NAME_LEN			32
 #define MAX_DA_RETRY_RACING_EVENTS	3
 
+#define RV_MON_GLOBAL	0
+#define RV_MON_PER_CPU	1
+#define RV_MON_PER_TASK	2
+
 #ifdef CONFIG_RV
 #include <linux/bitops.h>
 #include <linux/types.h>
diff --git a/include/rv/ltl_monitor.h b/include/rv/ltl_monitor.h
index 67031a774e3d..9dabc5b133a3 100644
--- a/include/rv/ltl_monitor.h
+++ b/include/rv/ltl_monitor.h
@@ -16,49 +16,63 @@
 #error "Please include $(MODEL_NAME).h generated by rvgen"
 #endif
 
+#if LTL_MONITOR_TYPE == RV_MON_PER_TASK
+
+#define TARGET_PRINT_FORMAT "%s[%d]"
+#define TARGET_PRINT_ARGS(task) task->comm, task->pid
+
+typedef struct task_struct *monitor_target;
+
+#endif
+
 #ifdef CONFIG_RV_REACTORS
 #define RV_MONITOR_NAME CONCATENATE(rv_, MONITOR_NAME)
 static struct rv_monitor RV_MONITOR_NAME;
 
-static void rv_cond_react(struct task_struct *task)
+static void rv_cond_react(monitor_target target)
 {
 	if (!rv_reacting_on() || !RV_MONITOR_NAME.react)
 		return;
-	RV_MONITOR_NAME.react("rv: "__stringify(MONITOR_NAME)": %s[%d]: violation detected\n",
-			      task->comm, task->pid);
+
+	RV_MONITOR_NAME.react(
+		"rv: "__stringify(MONITOR_NAME)": "TARGET_PRINT_FORMAT": violation detected\n",
+		TARGET_PRINT_ARGS(target));
 }
 #else
-static void rv_cond_react(struct task_struct *task)
+static void rv_cond_react(monitor_target target)
 {
 }
 #endif
 
-static int ltl_monitor_slot = RV_PER_TASK_MONITOR_INIT;
+static void ltl_atoms_fetch(monitor_target target, struct ltl_monitor *mon);
+static void ltl_atoms_init(monitor_target target, struct ltl_monitor *mon, bool target_creation);
 
-static void ltl_atoms_fetch(struct task_struct *task, struct ltl_monitor *mon);
-static void ltl_atoms_init(struct task_struct *task, struct ltl_monitor *mon, bool task_creation);
+#if LTL_MONITOR_TYPE == RV_MON_PER_TASK
+static int ltl_monitor_slot = RV_PER_TASK_MONITOR_INIT;
 
-static struct ltl_monitor *ltl_get_monitor(struct task_struct *task)
+static struct ltl_monitor *ltl_get_monitor(monitor_target target)
 {
-	return &task->rv[ltl_monitor_slot].ltl_mon;
+	return &target->rv[ltl_monitor_slot].ltl_mon;
 }
+#endif
 
-static void ltl_task_init(struct task_struct *task, bool task_creation)
+static void ltl_target_init(monitor_target target, bool target_creation)
 {
-	struct ltl_monitor *mon = ltl_get_monitor(task);
+	struct ltl_monitor *mon = ltl_get_monitor(target);
 
 	memset(&mon->states, 0, sizeof(mon->states));
 
 	for (int i = 0; i < LTL_NUM_ATOM; ++i)
 		__set_bit(i, mon->unknown_atoms);
 
-	ltl_atoms_init(task, mon, task_creation);
-	ltl_atoms_fetch(task, mon);
+	ltl_atoms_init(target, mon, target_creation);
+	ltl_atoms_fetch(target, mon);
 }
 
+#if LTL_MONITOR_TYPE == RV_MON_PER_TASK
 static void handle_task_newtask(void *data, struct task_struct *task, unsigned long flags)
 {
-	ltl_task_init(task, true);
+	ltl_target_init(task, true);
 }
 
 static int ltl_monitor_init(void)
@@ -77,10 +91,10 @@ static int ltl_monitor_init(void)
 	read_lock(&tasklist_lock);
 
 	for_each_process_thread(g, p)
-		ltl_task_init(p, false);
+		ltl_target_init(p, false);
 
 	for_each_present_cpu(cpu)
-		ltl_task_init(idle_task(cpu), false);
+		ltl_target_init(idle_task(cpu), false);
 
 	read_unlock(&tasklist_lock);
 
@@ -94,17 +108,18 @@ static void ltl_monitor_destroy(void)
 	rv_put_task_monitor_slot(ltl_monitor_slot);
 	ltl_monitor_slot = RV_PER_TASK_MONITOR_INIT;
 }
+#endif
 
-static void ltl_illegal_state(struct task_struct *task, struct ltl_monitor *mon)
+static void ltl_illegal_state(monitor_target target, struct ltl_monitor *mon)
 {
-	CONCATENATE(trace_error_, MONITOR_NAME)(task);
-	rv_cond_react(task);
+	CONCATENATE(trace_error_, MONITOR_NAME)(target);
+	rv_cond_react(target);
 }
 
-static void ltl_attempt_start(struct task_struct *task, struct ltl_monitor *mon)
+static void ltl_attempt_start(monitor_target target, struct ltl_monitor *mon)
 {
 	if (rv_ltl_all_atoms_known(mon))
-		ltl_start(task, mon);
+		ltl_start(target, mon);
 }
 
 static inline void ltl_atom_set(struct ltl_monitor *mon, enum ltl_atom atom, bool value)
@@ -117,7 +132,7 @@ static inline void ltl_atom_set(struct ltl_monitor *mon, enum ltl_atom atom, boo
 }
 
 static void
-ltl_trace_event(struct task_struct *task, struct ltl_monitor *mon, unsigned long *next_state)
+ltl_trace_event(monitor_target target, struct ltl_monitor *mon, unsigned long *next_state)
 {
 	const char *format_str = "%s";
 	DECLARE_SEQ_BUF(atoms, 64);
@@ -137,10 +152,10 @@ ltl_trace_event(struct task_struct *task, struct ltl_monitor *mon, unsigned long
 		}
 	}
 
-	CONCATENATE(trace_event_, MONITOR_NAME)(task, states, atoms.buffer, next);
+	CONCATENATE(trace_event_, MONITOR_NAME)(target, states, atoms.buffer, next);
 }
 
-static void ltl_validate(struct task_struct *task, struct ltl_monitor *mon)
+static void ltl_validate(monitor_target target, struct ltl_monitor *mon)
 {
 	DECLARE_BITMAP(next_states, RV_MAX_BA_STATES) = {0};
 
@@ -152,35 +167,35 @@ static void ltl_validate(struct task_struct *task, struct ltl_monitor *mon)
 			ltl_possible_next_states(mon, i, next_states);
 	}
 
-	ltl_trace_event(task, mon, next_states);
+	ltl_trace_event(target, mon, next_states);
 
 	memcpy(mon->states, next_states, sizeof(next_states));
 
 	if (!rv_ltl_valid_state(mon))
-		ltl_illegal_state(task, mon);
+		ltl_illegal_state(target, mon);
 }
 
-static void ltl_atom_update(struct task_struct *task, enum ltl_atom atom, bool value)
+static void ltl_atom_update(monitor_target target, enum ltl_atom atom, bool value)
 {
-	struct ltl_monitor *mon = ltl_get_monitor(task);
+	struct ltl_monitor *mon = ltl_get_monitor(target);
 
 	ltl_atom_set(mon, atom, value);
-	ltl_atoms_fetch(task, mon);
+	ltl_atoms_fetch(target, mon);
 
 	if (!rv_ltl_valid_state(mon)) {
-		ltl_attempt_start(task, mon);
+		ltl_attempt_start(target, mon);
 		return;
 	}
 
-	ltl_validate(task, mon);
+	ltl_validate(target, mon);
 }
 
-static void __maybe_unused ltl_atom_pulse(struct task_struct *task, enum ltl_atom atom, bool value)
+static void __maybe_unused ltl_atom_pulse(monitor_target target, enum ltl_atom atom, bool value)
 {
-	struct ltl_monitor *mon = ltl_get_monitor(task);
+	struct ltl_monitor *mon = ltl_get_monitor(target);
 
-	ltl_atom_update(task, atom, value);
+	ltl_atom_update(target, atom, value);
 
 	ltl_atom_set(mon, atom, !value);
-	ltl_validate(task, mon);
+	ltl_validate(target, mon);
 }
diff --git a/kernel/trace/rv/monitors/pagefault/pagefault.h b/kernel/trace/rv/monitors/pagefault/pagefault.h
index c580ec194009..d449af84c24c 100644
--- a/kernel/trace/rv/monitors/pagefault/pagefault.h
+++ b/kernel/trace/rv/monitors/pagefault/pagefault.h
@@ -11,6 +11,8 @@
 
 #define MONITOR_NAME pagefault
 
+#define LTL_MONITOR_TYPE RV_MON_PER_TASK
+
 enum ltl_atom {
 	LTL_PAGEFAULT,
 	LTL_RT,
diff --git a/kernel/trace/rv/monitors/sleep/sleep.h b/kernel/trace/rv/monitors/sleep/sleep.h
index 2ab46fd218d2..0c87875d9040 100644
--- a/kernel/trace/rv/monitors/sleep/sleep.h
+++ b/kernel/trace/rv/monitors/sleep/sleep.h
@@ -11,6 +11,8 @@
 
 #define MONITOR_NAME sleep
 
+#define LTL_MONITOR_TYPE RV_MON_PER_TASK
+
 enum ltl_atom {
 	LTL_ABORT_SLEEP,
 	LTL_BLOCK_ON_RT_MUTEX,
-- 
2.39.5

[PATCH v3 2/5] rv/ltl: Support per-cpu monitors

[Nam Cao]

Add support for per-cpu run-time verification linear temporal logic
monitors. This is analogous to deterministic automaton per-cpu monitors.

Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Nam Cao <namcao@linutronix.de>
---
v3: fixup build issue on sh4
v2: Rename "implicit" to "cpu"
---
 include/rv/ltl_monitor.h   | 32 ++++++++++++++++++++++++++
 kernel/trace/rv/Kconfig    |  4 ++++
 kernel/trace/rv/rv_trace.h | 46 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 82 insertions(+)

diff --git a/include/rv/ltl_monitor.h b/include/rv/ltl_monitor.h
index 9dabc5b133a3..5c0197a59db0 100644
--- a/include/rv/ltl_monitor.h
+++ b/include/rv/ltl_monitor.h
@@ -23,12 +23,21 @@
 
 typedef struct task_struct *monitor_target;
 
+#elif LTL_MONITOR_TYPE == RV_MON_PER_CPU
+
+#define TARGET_PRINT_FORMAT "%u"
+#define TARGET_PRINT_ARGS(cpu) cpu
+
+typedef unsigned int monitor_target;
+
 #endif
 
 #ifdef CONFIG_RV_REACTORS
 #define RV_MONITOR_NAME CONCATENATE(rv_, MONITOR_NAME)
 static struct rv_monitor RV_MONITOR_NAME;
 
+static struct ltl_monitor *ltl_get_monitor(monitor_target target);
+
 static void rv_cond_react(monitor_target target)
 {
 	if (!rv_reacting_on() || !RV_MONITOR_NAME.react)
@@ -54,6 +63,13 @@ static struct ltl_monitor *ltl_get_monitor(monitor_target target)
 {
 	return &target->rv[ltl_monitor_slot].ltl_mon;
 }
+#elif LTL_MONITOR_TYPE == RV_MON_PER_CPU
+static DEFINE_PER_CPU(struct ltl_monitor, ltl_monitor);
+
+static struct ltl_monitor *ltl_get_monitor(unsigned int cpu)
+{
+	return per_cpu_ptr(&ltl_monitor, cpu);
+}
 #endif
 
 static void ltl_target_init(monitor_target target, bool target_creation)
@@ -108,6 +124,22 @@ static void ltl_monitor_destroy(void)
 	rv_put_task_monitor_slot(ltl_monitor_slot);
 	ltl_monitor_slot = RV_PER_TASK_MONITOR_INIT;
 }
+
+#elif LTL_MONITOR_TYPE == RV_MON_PER_CPU
+
+static int ltl_monitor_init(void)
+{
+	unsigned int cpu;
+
+	for_each_possible_cpu(cpu)
+		ltl_target_init(cpu, false);
+	return 0;
+}
+
+static void ltl_monitor_destroy(void)
+{
+}
+
 #endif
 
 static void ltl_illegal_state(monitor_target target, struct ltl_monitor *mon)
diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
index 5b4be87ba59d..7ef89006ed50 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -16,6 +16,10 @@ config DA_MON_EVENTS_ID
 	select RV_MON_MAINTENANCE_EVENTS
 	bool
 
+config LTL_MON_EVENTS_CPU
+	select RV_MON_EVENTS
+	bool
+
 config LTL_MON_EVENTS_ID
 	select RV_MON_EVENTS
 	bool
diff --git a/kernel/trace/rv/rv_trace.h b/kernel/trace/rv/rv_trace.h
index 4a6faddac614..bf7cca6579ec 100644
--- a/kernel/trace/rv/rv_trace.h
+++ b/kernel/trace/rv/rv_trace.h
@@ -177,8 +177,54 @@ DECLARE_EVENT_CLASS(error_ltl_monitor_id,
 #include <monitors/pagefault/pagefault_trace.h>
 #include <monitors/sleep/sleep_trace.h>
 // Add new monitors based on CONFIG_LTL_MON_EVENTS_ID here
+
 #endif /* CONFIG_LTL_MON_EVENTS_ID */
 
+#ifdef CONFIG_LTL_MON_EVENTS_CPU
+DECLARE_EVENT_CLASS(event_ltl_monitor_cpu,
+
+	TP_PROTO(unsigned int cpu, char *states, char *atoms, char *next),
+
+	TP_ARGS(cpu, states, atoms, next),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, cpu)
+		__string(states, states)
+		__string(atoms, atoms)
+		__string(next, next)
+	),
+
+	TP_fast_assign(
+		__entry->cpu = cpu;
+		__assign_str(states);
+		__assign_str(atoms);
+		__assign_str(next);
+	),
+
+	TP_printk("cpu%u: (%s) x (%s) -> (%s)", __entry->cpu,
+		  __get_str(states), __get_str(atoms), __get_str(next))
+);
+
+DECLARE_EVENT_CLASS(error_ltl_monitor_cpu,
+
+	TP_PROTO(unsigned int cpu),
+
+	TP_ARGS(cpu),
+
+	TP_STRUCT__entry(
+		__field(unsigned int, cpu)
+	),
+
+	TP_fast_assign(
+		__entry->cpu = cpu;
+	),
+
+	TP_printk("cpu%u: violation detected", __entry->cpu)
+);
+// Add new monitors based on CONFIG_LTL_MON_EVENTS_CPU here
+
+#endif /* CONFIG_LTL_MON_EVENTS_CPU */
+
 #ifdef CONFIG_RV_MON_MAINTENANCE_EVENTS
 /* Tracepoint useful for monitors development, currenly only used in DA */
 TRACE_EVENT(rv_retries_error,
-- 
2.39.5

[PATCH v3 3/5] verification/rvgen/ltl: Support per-cpu monitor generation

[Nam Cao]

Add support to generate per-cpu LTL monitors. Similar to generating per-cpu
monitors from .dot files, the "-t per_cpu" parameter can be used to
generate per-cpu monitors from .ltl files.

Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Nam Cao <namcao@linutronix.de>
---
v3: re-write the description in ltl_atoms_init() to be more precise
v2: Rename "implicit" to "cpu"
---
 tools/verification/rvgen/rvgen/ltl2k.py       | 48 ++++++++++++++++---
 .../rvgen/rvgen/templates/ltl2k/main.c        |  9 ++--
 .../rvgen/rvgen/templates/ltl2k/trace.h       |  7 ++-
 3 files changed, 50 insertions(+), 14 deletions(-)

diff --git a/tools/verification/rvgen/rvgen/ltl2k.py b/tools/verification/rvgen/rvgen/ltl2k.py
index b075f98d50c4..f291d1f03d05 100644
--- a/tools/verification/rvgen/rvgen/ltl2k.py
+++ b/tools/verification/rvgen/rvgen/ltl2k.py
@@ -57,9 +57,16 @@ class ltl2k(generator.Monitor):
     template_dir = "ltl2k"
 
     def __init__(self, file_path, MonitorType, extra_params={}):
-        if MonitorType != "per_task":
-            raise NotImplementedError("Only per_task monitor is supported for LTL")
+        if MonitorType == "per_task":
+            self._target_arg = "struct task_struct *task"
+            self._target = "task"
+        elif MonitorType == "per_cpu":
+            self._target_arg = "unsigned int cpu"
+            self._target = "cpu"
+        else:
+            raise NotImplementedError(f"LTL does not support monitor type {MonitorType}")
         super().__init__(extra_params)
+        self.monitor_type = MonitorType
         with open(file_path) as f:
             self.atoms, self.ba, self.ltl = ltl2ba.create_graph(f.read())
         self.atoms_abbr = abbreviate_atoms(self.atoms)
@@ -67,6 +74,13 @@ class ltl2k(generator.Monitor):
         if not self.name:
             self.name = Path(file_path).stem
 
+    def _fill_monitor_type(self) -> str:
+        if self.monitor_type == "per_task":
+            return "#define LTL_MONITOR_TYPE RV_MON_PER_TASK"
+        if self.monitor_type == "per_cpu":
+            return "#define LTL_MONITOR_TYPE RV_MON_PER_CPU"
+        assert False
+
     def _fill_states(self) -> str:
         buf = [
             "enum ltl_buchi_state {",
@@ -174,7 +188,7 @@ class ltl2k(generator.Monitor):
 
     def _fill_start(self):
         buf = [
-            "static void ltl_start(struct task_struct *task, struct ltl_monitor *mon)",
+            "static void ltl_start(%s, struct ltl_monitor *mon)" % self._target_arg,
             "{"
         ]
 
@@ -205,7 +219,7 @@ class ltl2k(generator.Monitor):
         buff = []
         buff.append("static void handle_example_event(void *data, /* XXX: fill header */)")
         buff.append("{")
-        buff.append("\tltl_atom_update(task, LTL_%s, true/false);" % self.atoms[0])
+        buff.append("\tltl_atom_update(%s, LTL_%s, true/false);" % (self._target, self.atoms[0]))
         buff.append("}")
         buff.append("")
         return '\n'.join(buff)
@@ -241,6 +255,9 @@ class ltl2k(generator.Monitor):
             ""
         ]
 
+        buf.append(self._fill_monitor_type())
+        buf.append('')
+
         buf.extend(self._fill_atoms())
         buf.append('')
 
@@ -259,13 +276,32 @@ class ltl2k(generator.Monitor):
         return '\n'.join(buf)
 
     def fill_monitor_class_type(self):
-        return "LTL_MON_EVENTS_ID"
+        if self.monitor_type == "per_task":
+            return "LTL_MON_EVENTS_ID"
+        if self.monitor_type == "per_cpu":
+            return "LTL_MON_EVENTS_CPU"
+        assert False
 
     def fill_monitor_class(self):
-        return "ltl_monitor_id"
+        if self.monitor_type == "per_task":
+            return "ltl_monitor_id"
+        if self.monitor_type == "per_cpu":
+            return "ltl_monitor_cpu"
+        assert False
+
+    def fill_tracepoint_args_skel(self, tp_type):
+        if tp_type == "event":
+            return \
+                ("\tTP_PROTO(%s, char *states, char *atoms, char *next),\n" % self._target_arg) + \
+                ("\tTP_ARGS(%s, states, atoms, next)" % self._target)
+        if tp_type == "error":
+            return \
+                ("\tTP_PROTO(%s),\n" % self._target_arg) + \
+                ("\tTP_ARGS(%s)" % self._target)
 
     def fill_main_c(self):
         main_c = super().fill_main_c()
         main_c = main_c.replace("%%ATOMS_INIT%%", self.fill_atoms_init())
+        main_c = main_c.replace("%%TARGET_ARG%%", self._target_arg)
 
         return main_c
diff --git a/tools/verification/rvgen/rvgen/templates/ltl2k/main.c b/tools/verification/rvgen/rvgen/templates/ltl2k/main.c
index f85d076fbf78..c6b51a04c360 100644
--- a/tools/verification/rvgen/rvgen/templates/ltl2k/main.c
+++ b/tools/verification/rvgen/rvgen/templates/ltl2k/main.c
@@ -23,7 +23,7 @@
 #include "%%MODEL_NAME%%.h"
 #include <rv/ltl_monitor.h>
 
-static void ltl_atoms_fetch(struct task_struct *task, struct ltl_monitor *mon)
+static void ltl_atoms_fetch(%%TARGET_ARG%%, struct ltl_monitor *mon)
 {
 	/*
 	 * This is called everytime the Buchi automaton is triggered.
@@ -36,13 +36,14 @@ static void ltl_atoms_fetch(struct task_struct *task, struct ltl_monitor *mon)
 	 */
 }
 
-static void ltl_atoms_init(struct task_struct *task, struct ltl_monitor *mon, bool task_creation)
+static void ltl_atoms_init(%%TARGET_ARG%%, struct ltl_monitor *mon, bool target_creation)
 {
 	/*
 	 * This should initialize as many atomic propositions as possible.
 	 *
-	 * @task_creation indicates whether the task is being created. This is
-	 * false if the task is already running before the monitor is enabled.
+	 * @target_creation indicates whether the monitored target is being
+	 * created. This is false if the monitor target exists already before
+	 * the monitor is enabled.
 	 */
 %%ATOMS_INIT%%
 }
diff --git a/tools/verification/rvgen/rvgen/templates/ltl2k/trace.h b/tools/verification/rvgen/rvgen/templates/ltl2k/trace.h
index 49394c4b0f1c..87d3a1308926 100644
--- a/tools/verification/rvgen/rvgen/templates/ltl2k/trace.h
+++ b/tools/verification/rvgen/rvgen/templates/ltl2k/trace.h
@@ -6,9 +6,8 @@
 
 #ifdef CONFIG_RV_MON_%%MODEL_NAME_UP%%
 DEFINE_EVENT(event_%%MONITOR_CLASS%%, event_%%MODEL_NAME%%,
-	     TP_PROTO(struct task_struct *task, char *states, char *atoms, char *next),
-	     TP_ARGS(task, states, atoms, next));
+%%TRACEPOINT_ARGS_SKEL_EVENT%%);
+
 DEFINE_EVENT(error_%%MONITOR_CLASS%%, error_%%MODEL_NAME%%,
-	     TP_PROTO(struct task_struct *task),
-	     TP_ARGS(task));
+%%TRACEPOINT_ARGS_SKEL_ERROR%%);
 #endif /* CONFIG_RV_MON_%%MODEL_NAME_UP%% */
-- 
2.39.5

[PATCH v3 4/5] sched: Add task enqueue/dequeue trace points

[Nam Cao]

Add trace points into enqueue_task() and dequeue_task(). They are useful to
implement RV monitor which validates RT scheduling.

Signed-off-by: Nam Cao <namcao@linutronix.de>
---
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
---
v3: fix up build issue on !SMP
v2: Move the tracepoints to cover all task enqueue/dequeue, not just RT
---
 include/trace/events/sched.h | 13 +++++++++++++
 kernel/sched/core.c          |  8 +++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 7b2645b50e78..696d22af5a98 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -896,6 +896,19 @@ DECLARE_TRACE(sched_set_need_resched,
 	TP_PROTO(struct task_struct *tsk, int cpu, int tif),
 	TP_ARGS(tsk, cpu, tif));
 
+/*
+ * The two trace points below may not work as expected for fair tasks due
+ * to delayed dequeue. See:
+ * https://lore.kernel.org/lkml/179674c6-f82a-4718-ace2-67b5e672fdee@amd.com/
+ */
+DECLARE_TRACE(enqueue_task,
+	TP_PROTO(int cpu, struct task_struct *task),
+	TP_ARGS(cpu, task));
+
+DECLARE_TRACE(dequeue_task,
+	TP_PROTO(int cpu, struct task_struct *task),
+	TP_ARGS(cpu, task));
+
 #endif /* _TRACE_SCHED_H */
 
 /* This part must be outside protection */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index be00629f0ba4..6367799aa023 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2077,6 +2077,8 @@ unsigned long get_wchan(struct task_struct *p)
 
 void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
 {
+	trace_enqueue_task_tp(cpu_of(rq), p);
+
 	if (!(flags & ENQUEUE_NOCLOCK))
 		update_rq_clock(rq);
 
@@ -2119,7 +2121,11 @@ inline bool dequeue_task(struct rq *rq, struct task_struct *p, int flags)
 	 * and mark the task ->sched_delayed.
 	 */
 	uclamp_rq_dec(rq, p);
-	return p->sched_class->dequeue_task(rq, p, flags);
+	if (p->sched_class->dequeue_task(rq, p, flags)) {
+		trace_dequeue_task_tp(cpu_of(rq), p);
+		return true;
+	}
+	return false;
 }
 
 void activate_task(struct rq *rq, struct task_struct *p, int flags)
-- 
2.39.5

[PATCH v3 5/5] rv: Add rts monitor

[Nam Cao]

Add "real-time scheduling" monitor, which validates that SCHED_RR and
SCHED_FIFO tasks are scheduled before tasks with normal and extensible
scheduling policies

Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Nam Cao <namcao@linutronix.de>
---
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
---
v3:
  - move document file and specification file to be under rtapp
v2:
  - use the new tracepoints
  - move to be under the rtapp container monitor
  - re-generate with the modified scripts
  - fixup incorrect enqueued status
---
 Documentation/trace/rv/monitor_rtapp.rst |  19 +++
 kernel/trace/rv/Kconfig                  |   1 +
 kernel/trace/rv/Makefile                 |   1 +
 kernel/trace/rv/monitors/rts/Kconfig     |  17 +++
 kernel/trace/rv/monitors/rts/rts.c       | 144 +++++++++++++++++++++++
 kernel/trace/rv/monitors/rts/rts.h       | 126 ++++++++++++++++++++
 kernel/trace/rv/monitors/rts/rts_trace.h |  15 +++
 kernel/trace/rv/rv_trace.h               |   1 +
 tools/verification/models/rtapp/rts.ltl  |   5 +
 9 files changed, 329 insertions(+)
 create mode 100644 kernel/trace/rv/monitors/rts/Kconfig
 create mode 100644 kernel/trace/rv/monitors/rts/rts.c
 create mode 100644 kernel/trace/rv/monitors/rts/rts.h
 create mode 100644 kernel/trace/rv/monitors/rts/rts_trace.h
 create mode 100644 tools/verification/models/rtapp/rts.ltl

diff --git a/Documentation/trace/rv/monitor_rtapp.rst b/Documentation/trace/rv/monitor_rtapp.rst
index c8104eda924a..40001ace5612 100644
--- a/Documentation/trace/rv/monitor_rtapp.rst
+++ b/Documentation/trace/rv/monitor_rtapp.rst
@@ -131,3 +131,22 @@ special cases:
     real-time-safe because preemption is disabled for the duration.
   - `FUTEX_LOCK_PI` is included in the allowlist for the same reason as
     `BLOCK_ON_RT_MUTEX`.
+
+Monitor rts
++++++++++++
+
+The real-time scheduling monitor validates that tasks with real-time scheduling
+policies (`SCHED_FIFO` and `SCHED_RR`) are always scheduled before tasks with
+normal and extensible scheduling policies (`SCHED_OTHER`, `SCHED_BATCH`,
+`SCHED_IDLE`, `SCHED_EXT`):
+
+.. literalinclude:: ../../../tools/verification/models/rtapp/rts.ltl
+
+Note that this monitor may report errors if real-time throttling or fair
+deadline server is enabled. These mechanisms prevent real-time tasks from
+monopolying the CPU by giving tasks with normal and extensible scheduling
+policies a chance to run. They give system administrators a chance to kill a
+misbehaved real-time task. However, they violate the scheduling priorities and
+may cause latency to well-behaved real-time tasks. Thus, if you see errors from
+this monitor, consider disabling real-time throttling and the fair deadline
+server.
diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
index 7ef89006ed50..e9007ed32aea 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -67,6 +67,7 @@ source "kernel/trace/rv/monitors/opid/Kconfig"
 source "kernel/trace/rv/monitors/rtapp/Kconfig"
 source "kernel/trace/rv/monitors/pagefault/Kconfig"
 source "kernel/trace/rv/monitors/sleep/Kconfig"
+source "kernel/trace/rv/monitors/rts/Kconfig"
 # Add new rtapp monitors here
 
 # Add new monitors here
diff --git a/kernel/trace/rv/Makefile b/kernel/trace/rv/Makefile
index 750e4ad6fa0f..d7bfc7ae6677 100644
--- a/kernel/trace/rv/Makefile
+++ b/kernel/trace/rv/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_RV_MON_STS) += monitors/sts/sts.o
 obj-$(CONFIG_RV_MON_NRP) += monitors/nrp/nrp.o
 obj-$(CONFIG_RV_MON_SSSW) += monitors/sssw/sssw.o
 obj-$(CONFIG_RV_MON_OPID) += monitors/opid/opid.o
+obj-$(CONFIG_RV_MON_RTS) += monitors/rts/rts.o
 # Add new monitors here
 obj-$(CONFIG_RV_REACTORS) += rv_reactors.o
 obj-$(CONFIG_RV_REACT_PRINTK) += reactor_printk.o
diff --git a/kernel/trace/rv/monitors/rts/Kconfig b/kernel/trace/rv/monitors/rts/Kconfig
new file mode 100644
index 000000000000..5481b371bce1
--- /dev/null
+++ b/kernel/trace/rv/monitors/rts/Kconfig
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+config RV_MON_RTS
+	depends on RV
+	select RV_LTL_MONITOR
+	depends on RV_MON_RTAPP
+	default y
+	select LTL_MON_EVENTS_CPU
+	bool "rts monitor"
+	help
+	  Add support for RTS (real-time scheduling) monitor which validates
+	  that real-time-priority tasks are scheduled before SCHED_OTHER tasks.
+
+	  This monitor may report an error if RT throttling or deadline server
+	  is enabled.
+
+	  Say Y if you are debugging or testing a real-time system.
diff --git a/kernel/trace/rv/monitors/rts/rts.c b/kernel/trace/rv/monitors/rts/rts.c
new file mode 100644
index 000000000000..b4c3d3a4671d
--- /dev/null
+++ b/kernel/trace/rv/monitors/rts/rts.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/ftrace.h>
+#include <linux/tracepoint.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/rv.h>
+#include <linux/sched/deadline.h>
+#include <linux/sched/rt.h>
+#include <rv/instrumentation.h>
+
+#define MODULE_NAME "rts"
+
+#include <trace/events/sched.h>
+#include <rv_trace.h>
+#include <monitors/rtapp/rtapp.h>
+
+#include "rts.h"
+#include <rv/ltl_monitor.h>
+
+static DEFINE_PER_CPU(unsigned int, nr_queued);
+
+static void ltl_atoms_fetch(unsigned int cpu, struct ltl_monitor *mon)
+{
+}
+
+static void ltl_atoms_init(unsigned int cpu, struct ltl_monitor *mon,
+			   bool target_creation)
+{
+	ltl_atom_set(mon, LTL_SCHED_SWITCH, false);
+	ltl_atom_set(mon, LTL_SCHED_SWITCH_DL, false);
+	ltl_atom_set(mon, LTL_SCHED_SWITCH_RT, false);
+
+	/*
+	 * This may not be accurate, there may be enqueued RT tasks. But that's
+	 * okay, the worst we get is a false negative. It will be accurate as
+	 * soon as the CPU no longer has any queued RT task.
+	 */
+	ltl_atom_set(mon, LTL_RT_TASK_ENQUEUED, false);
+}
+
+static void handle_enqueue_task(void *data, int cpu, struct task_struct *task)
+{
+	unsigned int *queued = per_cpu_ptr(&nr_queued, cpu);
+
+	if (!rt_task(task))
+		return;
+
+	(*queued)++;
+	ltl_atom_update(cpu, LTL_RT_TASK_ENQUEUED, true);
+}
+
+static void handle_dequeue_task(void *data, int cpu, struct task_struct *task)
+{
+	unsigned int *queued = per_cpu_ptr(&nr_queued, cpu);
+
+	if (!rt_task(task))
+		return;
+
+	/*
+	 * This may not be accurate for a short time after the monitor is
+	 * enabled, because there may be enqueued RT tasks which are not counted
+	 * torward nr_queued. But that's okay, the worst we get is a false
+	 * negative. nr_queued will be accurate as soon as the CPU no longer has
+	 * any queued RT task.
+	 */
+	if (*queued)
+		(*queued)--;
+	if (!*queued)
+		ltl_atom_update(cpu, LTL_RT_TASK_ENQUEUED, false);
+}
+
+static void handle_sched_switch(void *data, bool preempt, struct task_struct *prev,
+				struct task_struct *next, unsigned int prev_state)
+{
+	unsigned int cpu = smp_processor_id();
+	struct ltl_monitor *mon = ltl_get_monitor(cpu);
+
+	ltl_atom_set(mon, LTL_SCHED_SWITCH_RT, rt_task(next));
+	ltl_atom_set(mon, LTL_SCHED_SWITCH_DL, dl_task(next));
+	ltl_atom_update(cpu, LTL_SCHED_SWITCH, true);
+
+	ltl_atom_set(mon, LTL_SCHED_SWITCH_RT, false);
+	ltl_atom_set(mon, LTL_SCHED_SWITCH_DL, false);
+	ltl_atom_update(cpu, LTL_SCHED_SWITCH, false);
+}
+
+static int enable_rts(void)
+{
+	unsigned int cpu;
+	int retval;
+
+	retval = ltl_monitor_init();
+	if (retval)
+		return retval;
+
+	for_each_possible_cpu(cpu) {
+		unsigned int *queued = per_cpu_ptr(&nr_queued, cpu);
+
+		*queued = 0;
+	}
+
+	rv_attach_trace_probe("rts", dequeue_task_tp, handle_dequeue_task);
+	rv_attach_trace_probe("rts", enqueue_task_tp, handle_enqueue_task);
+	rv_attach_trace_probe("rts", sched_switch, handle_sched_switch);
+
+	return 0;
+}
+
+static void disable_rts(void)
+{
+	rv_detach_trace_probe("rts", sched_switch, handle_sched_switch);
+	rv_detach_trace_probe("rts", enqueue_task_tp, handle_enqueue_task);
+	rv_detach_trace_probe("rts", dequeue_task_tp, handle_dequeue_task);
+
+	ltl_monitor_destroy();
+}
+
+/*
+ * This is the monitor register section.
+ */
+static struct rv_monitor rv_rts = {
+	.name = "rts",
+	.description = "Validate that real-time tasks are scheduled before lower-priority tasks",
+	.enable = enable_rts,
+	.disable = disable_rts,
+};
+
+static int __init register_rts(void)
+{
+	return rv_register_monitor(&rv_rts, &rv_rtapp);
+}
+
+static void __exit unregister_rts(void)
+{
+	rv_unregister_monitor(&rv_rts);
+}
+
+module_init(register_rts);
+module_exit(unregister_rts);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Nam Cao <namcao@linutronix.de>");
+MODULE_DESCRIPTION("rts: Validate that real-time tasks are scheduled before lower-priority tasks");
diff --git a/kernel/trace/rv/monitors/rts/rts.h b/kernel/trace/rv/monitors/rts/rts.h
new file mode 100644
index 000000000000..5881f30a38ce
--- /dev/null
+++ b/kernel/trace/rv/monitors/rts/rts.h
@@ -0,0 +1,126 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * C implementation of Buchi automaton, automatically generated by
+ * tools/verification/rvgen from the linear temporal logic specification.
+ * For further information, see kernel documentation:
+ *   Documentation/trace/rv/linear_temporal_logic.rst
+ */
+
+#include <linux/rv.h>
+
+#define MONITOR_NAME rts
+
+#define LTL_MONITOR_TYPE RV_MON_PER_CPU
+
+enum ltl_atom {
+	LTL_RT_TASK_ENQUEUED,
+	LTL_SCHED_SWITCH,
+	LTL_SCHED_SWITCH_DL,
+	LTL_SCHED_SWITCH_RT,
+	LTL_NUM_ATOM
+};
+static_assert(LTL_NUM_ATOM <= RV_MAX_LTL_ATOM);
+
+static const char *ltl_atom_str(enum ltl_atom atom)
+{
+	static const char *const names[] = {
+		"rt_ta_en",
+		"sc_sw",
+		"sc_sw_dl",
+		"sc_sw_rt",
+	};
+
+	return names[atom];
+}
+
+enum ltl_buchi_state {
+	S0,
+	S1,
+	S2,
+	S3,
+	S4,
+	RV_NUM_BA_STATES
+};
+static_assert(RV_NUM_BA_STATES <= RV_MAX_BA_STATES);
+
+static void ltl_start(unsigned int cpu, struct ltl_monitor *mon)
+{
+	bool sched_switch_rt = test_bit(LTL_SCHED_SWITCH_RT, mon->atoms);
+	bool sched_switch_dl = test_bit(LTL_SCHED_SWITCH_DL, mon->atoms);
+	bool sched_switch = test_bit(LTL_SCHED_SWITCH, mon->atoms);
+	bool rt_task_enqueued = test_bit(LTL_RT_TASK_ENQUEUED, mon->atoms);
+	bool val13 = !rt_task_enqueued;
+	bool val8 = sched_switch_dl || val13;
+	bool val9 = sched_switch_rt || val8;
+	bool val6 = !sched_switch;
+	bool val1 = !rt_task_enqueued;
+
+	if (val1)
+		__set_bit(S0, mon->states);
+	if (val6)
+		__set_bit(S1, mon->states);
+	if (val9)
+		__set_bit(S4, mon->states);
+}
+
+static void
+ltl_possible_next_states(struct ltl_monitor *mon, unsigned int state, unsigned long *next)
+{
+	bool sched_switch_rt = test_bit(LTL_SCHED_SWITCH_RT, mon->atoms);
+	bool sched_switch_dl = test_bit(LTL_SCHED_SWITCH_DL, mon->atoms);
+	bool sched_switch = test_bit(LTL_SCHED_SWITCH, mon->atoms);
+	bool rt_task_enqueued = test_bit(LTL_RT_TASK_ENQUEUED, mon->atoms);
+	bool val13 = !rt_task_enqueued;
+	bool val8 = sched_switch_dl || val13;
+	bool val9 = sched_switch_rt || val8;
+	bool val6 = !sched_switch;
+	bool val1 = !rt_task_enqueued;
+
+	switch (state) {
+	case S0:
+		if (val1)
+			__set_bit(S0, next);
+		if (val6)
+			__set_bit(S1, next);
+		if (val9)
+			__set_bit(S4, next);
+		break;
+	case S1:
+		if (val6)
+			__set_bit(S1, next);
+		if (val1 && val6)
+			__set_bit(S2, next);
+		if (val1 && val9)
+			__set_bit(S3, next);
+		if (val9)
+			__set_bit(S4, next);
+		break;
+	case S2:
+		if (val6)
+			__set_bit(S1, next);
+		if (val1 && val6)
+			__set_bit(S2, next);
+		if (val1 && val9)
+			__set_bit(S3, next);
+		if (val9)
+			__set_bit(S4, next);
+		break;
+	case S3:
+		if (val1)
+			__set_bit(S0, next);
+		if (val6)
+			__set_bit(S1, next);
+		if (val9)
+			__set_bit(S4, next);
+		break;
+	case S4:
+		if (val1)
+			__set_bit(S0, next);
+		if (val6)
+			__set_bit(S1, next);
+		if (val9)
+			__set_bit(S4, next);
+		break;
+	}
+}
diff --git a/kernel/trace/rv/monitors/rts/rts_trace.h b/kernel/trace/rv/monitors/rts/rts_trace.h
new file mode 100644
index 000000000000..ac4ea84162f7
--- /dev/null
+++ b/kernel/trace/rv/monitors/rts/rts_trace.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Snippet to be included in rv_trace.h
+ */
+
+#ifdef CONFIG_RV_MON_RTS
+DEFINE_EVENT(event_ltl_monitor_cpu, event_rts,
+	TP_PROTO(unsigned int cpu, char *states, char *atoms, char *next),
+	TP_ARGS(cpu, states, atoms, next));
+
+DEFINE_EVENT(error_ltl_monitor_cpu, error_rts,
+	TP_PROTO(unsigned int cpu),
+	TP_ARGS(cpu));
+#endif /* CONFIG_RV_MON_RTS */
diff --git a/kernel/trace/rv/rv_trace.h b/kernel/trace/rv/rv_trace.h
index bf7cca6579ec..7b3a6fb8ca6f 100644
--- a/kernel/trace/rv/rv_trace.h
+++ b/kernel/trace/rv/rv_trace.h
@@ -221,6 +221,7 @@ DECLARE_EVENT_CLASS(error_ltl_monitor_cpu,
 
 	TP_printk("cpu%u: violation detected", __entry->cpu)
 );
+#include <monitors/rts/rts_trace.h>
 // Add new monitors based on CONFIG_LTL_MON_EVENTS_CPU here
 
 #endif /* CONFIG_LTL_MON_EVENTS_CPU */
diff --git a/tools/verification/models/rtapp/rts.ltl b/tools/verification/models/rtapp/rts.ltl
new file mode 100644
index 000000000000..90872bca46b1
--- /dev/null
+++ b/tools/verification/models/rtapp/rts.ltl
@@ -0,0 +1,5 @@
+RULE = always (RT_TASK_ENQUEUED imply SCHEDULE_RT_NEXT)
+
+SCHEDULE_RT_NEXT = (not SCHED_SWITCH) until (SCHED_SWITCH_RT or EXCEPTIONS)
+
+EXCEPTIONS = SCHED_SWITCH_DL or not RT_TASK_ENQUEUED
-- 
2.39.5

Re: [PATCH v3 4/5] sched: Add task enqueue/dequeue trace points

[Gabriele Monaco]

On Mon, 2025-08-11 at 10:40 +0200, Nam Cao wrote:
> Add trace points into enqueue_task() and dequeue_task(). They are
> useful to implement RV monitor which validates RT scheduling.
> 
> Signed-off-by: Nam Cao <namcao@linutronix.de>
> ---

Peter, Ingo, this patch adds new tracepoints in the scheduler do agree
with the change, can we get an Ack?

Thanks,
Gabriele

> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Juri Lelli <juri.lelli@redhat.com>
> Cc: Vincent Guittot <vincent.guittot@linaro.org>
> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
> Cc: Ben Segall <bsegall@google.com>
> Cc: Mel Gorman <mgorman@suse.de>
> Cc: Valentin Schneider <vschneid@redhat.com>
> Cc: K Prateek Nayak <kprateek.nayak@amd.com>
> ---
> v3: fix up build issue on !SMP
> v2: Move the tracepoints to cover all task enqueue/dequeue, not just
> RT
> ---
>  include/trace/events/sched.h | 13 +++++++++++++
>  kernel/sched/core.c          |  8 +++++++-
>  2 files changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/include/trace/events/sched.h
> b/include/trace/events/sched.h
> index 7b2645b50e78..696d22af5a98 100644
> --- a/include/trace/events/sched.h
> +++ b/include/trace/events/sched.h
> @@ -896,6 +896,19 @@ DECLARE_TRACE(sched_set_need_resched,
>  	TP_PROTO(struct task_struct *tsk, int cpu, int tif),
>  	TP_ARGS(tsk, cpu, tif));
>  
> +/*
> + * The two trace points below may not work as expected for fair
> tasks due
> + * to delayed dequeue. See:
> + *
> https://lore.kernel.org/lkml/179674c6-f82a-4718-ace2-67b5e672fdee@amd.com/
> + */
> +DECLARE_TRACE(enqueue_task,
> +	TP_PROTO(int cpu, struct task_struct *task),
> +	TP_ARGS(cpu, task));
> +
> +DECLARE_TRACE(dequeue_task,
> +	TP_PROTO(int cpu, struct task_struct *task),
> +	TP_ARGS(cpu, task));
> +
>  #endif /* _TRACE_SCHED_H */
>  
>  /* This part must be outside protection */
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index be00629f0ba4..6367799aa023 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -2077,6 +2077,8 @@ unsigned long get_wchan(struct task_struct *p)
>  
>  void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
>  {
> +	trace_enqueue_task_tp(cpu_of(rq), p);
> +
>  	if (!(flags & ENQUEUE_NOCLOCK))
>  		update_rq_clock(rq);
>  
> @@ -2119,7 +2121,11 @@ inline bool dequeue_task(struct rq *rq, struct
> task_struct *p, int flags)
>  	 * and mark the task ->sched_delayed.
>  	 */
>  	uclamp_rq_dec(rq, p);
> -	return p->sched_class->dequeue_task(rq, p, flags);
> +	if (p->sched_class->dequeue_task(rq, p, flags)) {
> +		trace_dequeue_task_tp(cpu_of(rq), p);
> +		return true;
> +	}
> +	return false;
>  }
>  
>  void activate_task(struct rq *rq, struct task_struct *p, int flags)