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rv: Do not rely on clean monitor when initialising HA

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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@linux.dev>
Closes: https://lore.kernel.org/lkml/d02c656aada7d071f083460a5c9a454363669b61.1778522945.git.wen.yang@linux.dev
Suggested-by: Nam Cao <namcao@linutronix.de>
Fixes: f5587d1b6e ("rv: Add Hybrid Automata monitor type")
Reviewed-by: Wen Yang <wen.yang@linux.dev>
Reviewed-by: Nam Cao <namcao@linutronix.de>
Link: https://lore.kernel.org/r/20260601153840.124372-7-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
This commit is contained in:
Gabriele Monaco 2026-06-01 17:38:33 +02:00
parent 2b9a8c2741
commit 713c9e1ea7
2 changed files with 76 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

91
include/rv/da_monitor.h
View File

@ -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)

2
include/rv/ha_monitor.h
View File

@ -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);
}