rv: Reset per-task monitors also for idle tasks

commit 8259cb14a70680553d5e82d65d1302fe589e9b39 upstream.

RV per-task monitors are implemented through a monitor structure
available for each task_struct. This structure is reset every time the
monitor is (re-)started, to avoid inconsistencies if the monitor was
activated previously.
To do so, we reset the monitor on all threads using the macro
for_each_process_thread. However, this macro excludes the idle tasks on
each CPU. Idle tasks could be considered tasks on their own right and it
should be up to the model whether to ignore them or not.

Reset monitors also on the idle tasks for each present CPU whenever we
reset all per-task monitors.

Cc: stable@vger.kernel.org
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Kacur <jkacur@redhat.com>
Link: https://lore.kernel.org/20250115151547.605750-2-gmonaco@redhat.com


Fixes: 79257534 ("rv/include: Add deterministic automata monitor definition via C macros")
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/rv/da_monitor.h

@@ -14,6 +14,7 @@
 #include <rv/automata.h>
 #include <linux/rv.h>
 #include <linux/bug.h>
+#include <linux/sched.h>
 
 #ifdef CONFIG_RV_REACTORS
 
@@ -324,10 +325,13 @@ static inline struct da_monitor *da_get_monitor_##name(struct task_struct *tsk)
 static void da_monitor_reset_all_##name(void)							\
 {												\
 	struct task_struct *g, *p;								\
+	int cpu;										\
 												\
 	read_lock(&tasklist_lock);								\
 	for_each_process_thread(g, p)								\
 		da_monitor_reset_##name(da_get_monitor_##name(p));				\
+	for_each_present_cpu(cpu)								\
+		da_monitor_reset_##name(da_get_monitor_##name(idle_task(cpu)));			\
 	read_unlock(&tasklist_lock);								\
 }												\
 												\