[PATCH v4 06/13] rv: Do not rely on clean monitor when initialising HA
From: Gabriele Monaco
Date: Mon Jun 01 2026 - 12:03:02 EST
Hybrid Automata monitors hook into the DA implementation when doing
da_monitor_reset(). This function is called both on initialisation and
teardown, HA monitors try to cancel a timer only when it's initialised
relying on the da_mon->monitoring flag. This flag could however be
corrupted during initialisation. This happens for instance on per-task
monitors that share the same storage with different type of monitors
like LTL or in case of races during a previous teardown.
Stop relying on the monitoring flag during initialisation, assume that
can have any value, so use a separate da_reset_state() skiping timer
cancellation.
New monitors (e.g. new tasks) are always zero-initialised so it is safe
to rely on the monitoring flag for those.
Reported-by: Wen Yang <wen.yang@xxxxxxxxx>
Closes: https://lore.kernel.org/lkml/d02c656aada7d071f083460a5c9a454363669b61.1778522945.git.wen.yang@xxxxxxxxx
Suggested-by: Nam Cao <namcao@xxxxxxxxxxxxx>
Fixes: f5587d1b6ec9 ("rv: Add Hybrid Automata monitor type")
Reviewed-by: Wen Yang <wen.yang@xxxxxxxxx>
Signed-off-by: Gabriele Monaco <gmonaco@xxxxxxxxxx>
---
include/rv/da_monitor.h | 91 +++++++++++++++++++++++++++++++++--------
include/rv/ha_monitor.h | 2 +-
2 files changed, 76 insertions(+), 17 deletions(-)
diff --git a/include/rv/da_monitor.h b/include/rv/da_monitor.h
index 60dc39f26..ec9bc88bd 100644
--- a/include/rv/da_monitor.h
+++ b/include/rv/da_monitor.h
@@ -76,14 +76,22 @@ static void react(enum states curr_state, enum events event)
model_get_state_name(curr_state));
}
+/*
+ * da_monitor_reset_state - reset a monitor and setting it to init state
+ */
+static inline void da_monitor_reset_state(struct da_monitor *da_mon)
+{
+ WRITE_ONCE(da_mon->monitoring, 0);
+ da_mon->curr_state = model_get_initial_state();
+}
+
/*
* da_monitor_reset - reset a monitor and setting it to init state
*/
static inline void da_monitor_reset(struct da_monitor *da_mon)
{
da_monitor_reset_hook(da_mon);
- WRITE_ONCE(da_mon->monitoring, 0);
- da_mon->curr_state = model_get_initial_state();
+ da_monitor_reset_state(da_mon);
}
/*
@@ -158,12 +166,28 @@ static struct da_monitor *da_get_monitor(void)
return &DA_MON_NAME;
}
+/*
+ * __da_monitor_reset_all - reset the single monitor
+ */
+static void __da_monitor_reset_all(void (*reset)(struct da_monitor *))
+{
+ reset(da_get_monitor());
+}
+
/*
* da_monitor_reset_all - reset the single monitor
*/
static void da_monitor_reset_all(void)
{
- da_monitor_reset(da_get_monitor());
+ __da_monitor_reset_all(da_monitor_reset);
+}
+
+/*
+ * da_monitor_reset_state_all - reset the single monitor
+ */
+static inline void da_monitor_reset_state_all(void)
+{
+ __da_monitor_reset_all(da_monitor_reset_state);
}
/*
@@ -171,7 +195,7 @@ static void da_monitor_reset_all(void)
*/
static inline int da_monitor_init(void)
{
- da_monitor_reset_all();
+ da_monitor_reset_state_all();
return 0;
}
@@ -202,25 +226,41 @@ static struct da_monitor *da_get_monitor(void)
}
/*
- * da_monitor_reset_all - reset all CPUs' monitor
+ * __da_monitor_reset_all - reset all CPUs' monitor
*/
-static void da_monitor_reset_all(void)
+static void __da_monitor_reset_all(void (*reset)(struct da_monitor *))
{
struct da_monitor *da_mon;
int cpu;
for_each_cpu(cpu, cpu_online_mask) {
da_mon = per_cpu_ptr(&DA_MON_NAME, cpu);
- da_monitor_reset(da_mon);
+ reset(da_mon);
}
}
+/*
+ * da_monitor_reset_all - reset all CPUs' monitor
+ */
+static void da_monitor_reset_all(void)
+{
+ __da_monitor_reset_all(da_monitor_reset);
+}
+
+/*
+ * da_monitor_reset_state_all - reset all CPUs' monitor
+ */
+static inline void da_monitor_reset_state_all(void)
+{
+ __da_monitor_reset_all(da_monitor_reset_state);
+}
+
/*
* da_monitor_init - initialize all CPUs' monitor
*/
static inline int da_monitor_init(void)
{
- da_monitor_reset_all();
+ da_monitor_reset_state_all();
return 0;
}
@@ -269,19 +309,29 @@ static inline da_id_type da_get_id(struct da_monitor *da_mon)
return da_get_target(da_mon)->pid;
}
-static void da_monitor_reset_all(void)
+static void __da_monitor_reset_all(void (*reset)(struct da_monitor *))
{
struct task_struct *g, *p;
int cpu;
read_lock(&tasklist_lock);
for_each_process_thread(g, p)
- da_monitor_reset(da_get_monitor(p));
+ reset(da_get_monitor(p));
for_each_present_cpu(cpu)
- da_monitor_reset(da_get_monitor(idle_task(cpu)));
+ reset(da_get_monitor(idle_task(cpu)));
read_unlock(&tasklist_lock);
}
+static void da_monitor_reset_all(void)
+{
+ __da_monitor_reset_all(da_monitor_reset);
+}
+
+static inline void da_monitor_reset_state_all(void)
+{
+ __da_monitor_reset_all(da_monitor_reset_state);
+}
+
/*
* da_monitor_init - initialize the per-task monitor
*
@@ -298,7 +348,7 @@ static int da_monitor_init(void)
task_mon_slot = slot;
- da_monitor_reset_all();
+ da_monitor_reset_state_all();
return 0;
}
@@ -490,15 +540,24 @@ static inline void da_destroy_storage(da_id_type id)
kfree_rcu(mon_storage, rcu);
}
-static void da_monitor_reset_all(void)
+static void __da_monitor_reset_all(void (*reset)(struct da_monitor *))
{
struct da_monitor_storage *mon_storage;
int bkt;
- rcu_read_lock();
+ guard(rcu)();
hash_for_each_rcu(da_monitor_ht, bkt, mon_storage, node)
- da_monitor_reset(&mon_storage->rv.da_mon);
- rcu_read_unlock();
+ reset(&mon_storage->rv.da_mon);
+}
+
+static void da_monitor_reset_all(void)
+{
+ __da_monitor_reset_all(da_monitor_reset);
+}
+
+static inline void da_monitor_reset_state_all(void)
+{
+ __da_monitor_reset_all(da_monitor_reset_state);
}
static inline int da_monitor_init(void)
diff --git a/include/rv/ha_monitor.h b/include/rv/ha_monitor.h
index d59507e8c..bd8705556 100644
--- a/include/rv/ha_monitor.h
+++ b/include/rv/ha_monitor.h
@@ -153,12 +153,12 @@ static inline void ha_monitor_init_env(struct da_monitor *da_mon)
* Called from a hook in the DA reset functions, it supplies the da_mon
* corresponding to the current ha_mon.
* Not all hybrid automata require the timer, still clear it for simplicity.
+ * Monitors that never started have their timer uninitialized, do not stop those.
*/
static inline void ha_monitor_reset_env(struct da_monitor *da_mon)
{
struct ha_monitor *ha_mon = to_ha_monitor(da_mon);
- /* Initialisation resets the monitor before initialising the timer */
if (likely(da_monitoring(da_mon)))
ha_cancel_timer(ha_mon);
}
--
2.54.0