Hi Steven and Greg,
On Thu, 27 Apr 2023 at 15:19, Naresh Kamboju naresh.kamboju@linaro.org wrote:
Hi Steven,
On Wed, 26 Apr 2023 at 23:14, Steven Rostedt rostedt@goodmis.org wrote:
On Wed, 26 Apr 2023 17:09:45 -0400 Steven Rostedt rostedt@goodmis.org wrote:
Now the question is, why is this triggering on 4.19 but not in latest mainline?
I found it, I backported this patch and the warning goes away (at least for me). Can you add this and see if it makes the warning go away for you too?
I have applied this patch on stable-rc 4.19 branch and tested on
- arm64: Juno-r2
- x86_64 device
and the reported problem has been resolved.
Thanks for finding a quick fix patch.
-- Steve
From: Peter Zijlstra peterz@infradead.org Date: Fri, 7 Aug 2020 20:50:19 +0200 Subject: [PATCH] sched,idle,rcu: Push rcu_idle deeper into the idle path
commit 1098582a0f6c4e8fd28da0a6305f9233d02c9c1d upstream.
Can we expect this patch to be merged into 4.19 ? The reason for the question is, the reported problem is still seen on stable-rc 4.19.
Lots of things take locks, due to a wee bug, rcu_lockdep didn't notice that the locking tracepoints were using RCU.
Push rcu_idle_{enter,exit}() as deep as possible into the idle paths, this also resolves a lot of _rcuidle()/RCU_NONIDLE() usage.
Specifically, sched_clock_idle_wakeup_event() will use ktime which will use seqlocks which will tickle lockdep, and stop_critical_timings() uses lock.
Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Reviewed-by: Steven Rostedt (VMware) rostedt@goodmis.org Reviewed-by: Thomas Gleixner tglx@linutronix.de Acked-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Tested-by: Marco Elver elver@google.com Link: https://lkml.kernel.org/r/20200821085348.310943801@infradead.org
Tested-by: Linux Kernel Functional Testing lkft@linaro.org Tested-by: Naresh Kamboju naresh.kamboju@linaro.org
test log:
- https://lkft.validation.linaro.org/scheduler/job/6380295#L1418
- https://lkft.validation.linaro.org/scheduler/job/6380303#L1443
drivers/cpuidle/cpuidle.c | 12 ++++++++---- kernel/sched/idle.c | 22 ++++++++-------------- 2 files changed, 16 insertions(+), 18 deletions(-)
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 2d182dc1b49e..01bde6dec13a 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -140,13 +140,14 @@ static void enter_s2idle_proper(struct cpuidle_driver *drv, * executing it contains RCU usage regarded as invalid in the idle * context, so tell RCU about that. */
RCU_NONIDLE(tick_freeze());
tick_freeze(); /* * The state used here cannot be a "coupled" one, because the "coupled" * cpuidle mechanism enables interrupts and doing that with timekeeping * suspended is generally unsafe. */ stop_critical_timings();rcu_idle_enter(); drv->states[index].enter_s2idle(dev, drv, index); if (WARN_ON_ONCE(!irqs_disabled())) local_irq_disable();@@ -155,7 +156,8 @@ static void enter_s2idle_proper(struct cpuidle_driver *drv, * first CPU executing it calls functions containing RCU read-side * critical sections, so tell RCU about that. */
RCU_NONIDLE(tick_unfreeze());
rcu_idle_exit();tick_unfreeze(); start_critical_timings(); time_end = ns_to_ktime(local_clock());@@ -224,16 +226,18 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, /* Take note of the planned idle state. */ sched_idle_set_state(target_state);
trace_cpu_idle_rcuidle(index, dev->cpu);
trace_cpu_idle(index, dev->cpu); time_start = ns_to_ktime(local_clock()); stop_critical_timings();rcu_idle_enter(); entered_state = target_state->enter(dev, drv, index);rcu_idle_exit(); start_critical_timings(); sched_clock_idle_wakeup_event(); time_end = ns_to_ktime(local_clock());
trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
trace_cpu_idle(PWR_EVENT_EXIT, dev->cpu); /* The cpu is no longer idle or about to enter idle. */ sched_idle_set_state(NULL);diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 44a17366c8ec..4e3d149d64ad 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -53,17 +53,18 @@ __setup("hlt", cpu_idle_nopoll_setup);
static noinline int __cpuidle cpu_idle_poll(void) {
trace_cpu_idle(0, smp_processor_id());stop_critical_timings(); rcu_idle_enter();
trace_cpu_idle_rcuidle(0, smp_processor_id()); local_irq_enable();stop_critical_timings(); while (!tif_need_resched() &&(cpu_idle_force_poll || tick_check_broadcast_expired()))
(cpu_idle_force_poll || tick_check_broadcast_expired())) cpu_relax();
start_critical_timings();trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
rcu_idle_exit();start_critical_timings();trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id()); return 1;} @@ -90,7 +91,9 @@ void __cpuidle default_idle_call(void) local_irq_enable(); } else { stop_critical_timings();
rcu_idle_enter(); arch_cpu_idle();rcu_idle_exit(); start_critical_timings(); }} @@ -148,7 +151,6 @@ static void cpuidle_idle_call(void)
if (cpuidle_not_available(drv, dev)) { tick_nohz_idle_stop_tick();
rcu_idle_enter(); default_idle_call(); goto exit_idle;@@ -166,19 +168,15 @@ static void cpuidle_idle_call(void)
if (idle_should_enter_s2idle() || dev->use_deepest_state) { if (idle_should_enter_s2idle()) {
rcu_idle_enter(); entered_state = cpuidle_enter_s2idle(drv, dev); if (entered_state > 0) { local_irq_enable(); goto exit_idle; }rcu_idle_exit(); } tick_nohz_idle_stop_tick();rcu_idle_enter(); next_state = cpuidle_find_deepest_state(drv, dev); call_cpuidle(drv, dev, next_state);@@ -195,8 +193,6 @@ static void cpuidle_idle_call(void) else tick_nohz_idle_retain_tick();
rcu_idle_enter();entered_state = call_cpuidle(drv, dev, next_state); /* * Give the governor an opportunity to reflect on the outcome@@ -212,8 +208,6 @@ static void cpuidle_idle_call(void) */ if (WARN_ON_ONCE(irqs_disabled())) local_irq_enable();
rcu_idle_exit();}
/*
2.39.2
- Naresh
-- Linaro LKFT https://lkft.linaro.org