From: peterz@infradead.org
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, will@kernel.org,
npiggin@gmail.com, elver@google.com, jgross@suse.com,
paulmck@kernel.org, rjw@rjwysocki.net, joel@joelfernandes.org,
svens@linux.ibm.com, tglx@linutronix.de
Subject: Re: [PATCH 0/9] TRACE_IRQFLAGS wreckage
Date: Thu, 20 Aug 2020 16:58:21 +0200 [thread overview]
Message-ID: <20200820145821.GA1362448@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200820103643.1b9abe88@oasis.local.home>
On Thu, Aug 20, 2020 at 10:36:43AM -0400, Steven Rostedt wrote:
>
> I tested this series on top of tip/master and triggered the below
> warning when running the irqsoff tracer boot up test (config attached).
>
> -- Steve
>
> Testing tracer irqsoff:
>
> =============================
> WARNING: suspicious RCU usage
> 5.9.0-rc1-test+ #92 Not tainted
> -----------------------------
> include/trace/events/lock.h:13 suspicious rcu_dereference_check() usage!
>
> other info that might help us debug this:
>
>
> rcu_scheduler_active = 2, debug_locks = 1
> RCU used illegally from extended quiescent state!
> no locks held by swapper/2/0.
>
> stack backtrace:
> CPU: 2 PID: 0 Comm: swapper/2 Not tainted 5.9.0-rc1-test+ #92
> Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v03.03 07/14/2016
> Call Trace:
> dump_stack+0x8d/0xc0
> lock_acquire.cold+0x23/0x2c
> ? default_idle_call+0x4d/0x210
> _raw_spin_lock_irqsave+0x50/0xa0
> ? check_critical_timing+0x69/0x160
> check_critical_timing+0x69/0x160
> ? default_idle_call+0x4d/0x210
> stop_critical_timings+0xdd/0xf0
> default_idle_call+0x4d/0x210
> do_idle+0x1f6/0x260
> cpu_startup_entry+0x19/0x20
> start_secondary+0x110/0x140
> secondary_startup_64+0xb6/0xc0
Shiny, I think that wants something like the below, but let me go frob
my config and test it.
---
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -151,8 +151,8 @@ static void enter_s2idle_proper(struct c
* cpuidle mechanism enables interrupts and doing that with timekeeping
* suspended is generally unsafe.
*/
- rcu_idle_enter();
stop_critical_timings();
+ rcu_idle_enter();
drv->states[index].enter_s2idle(dev, drv, index);
if (WARN_ON_ONCE(!irqs_disabled()))
local_irq_disable();
@@ -164,8 +164,8 @@ static void enter_s2idle_proper(struct c
* FIXME, order against rcu_idle_exit ?
*/
RCU_NONIDLE(tick_unfreeze());
- start_critical_timings();
rcu_idle_exit();
+ start_critical_timings();
time_end = ns_to_ktime(local_clock());
@@ -236,11 +236,11 @@ int cpuidle_enter_state(struct cpuidle_d
trace_cpu_idle(index, dev->cpu);
time_start = ns_to_ktime(local_clock());
- rcu_idle_enter();
stop_critical_timings();
+ rcu_idle_enter();
entered_state = target_state->enter(dev, drv, index);
- start_critical_timings();
rcu_idle_exit();
+ start_critical_timings();
sched_clock_idle_wakeup_event();
time_end = ns_to_ktime(local_clock());
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -55,16 +55,16 @@ __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();
local_irq_enable();
- stop_critical_timings();
while (!tif_need_resched() &&
(cpu_idle_force_poll || tick_check_broadcast_expired()))
cpu_relax();
- start_critical_timings();
rcu_idle_exit();
+ start_critical_timings();
trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id());
return 1;
@@ -91,11 +91,11 @@ void __cpuidle default_idle_call(void)
if (current_clr_polling_and_test()) {
local_irq_enable();
} else {
- rcu_idle_enter();
stop_critical_timings();
+ rcu_idle_enter();
arch_cpu_idle();
- start_critical_timings();
rcu_idle_exit();
+ start_critical_timings();
}
}
next prev parent reply other threads:[~2020-08-20 14:58 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-20 7:30 [PATCH 0/9] TRACE_IRQFLAGS wreckage Peter Zijlstra
2020-08-20 7:30 ` [PATCH 1/9] lockdep: Use raw_cpu_*() for per-cpu variables Peter Zijlstra
2020-08-20 13:54 ` Steven Rostedt
2020-08-20 7:30 ` [PATCH 2/9] sched,idle,rcu: Push rcu_idle deeper into the idle path Peter Zijlstra
2020-08-20 13:58 ` Steven Rostedt
2020-08-20 7:30 ` [PATCH 3/9] cpuidle: Make CPUIDLE_FLAG_TLB_FLUSHED generic Peter Zijlstra
2020-08-20 7:30 ` [PATCH 4/9] cpuidle: Move trace_cpu_idle() into generic code Peter Zijlstra
2020-08-20 7:30 ` [PATCH 5/9] x86/entry: Remove unused THUNKs Peter Zijlstra
2020-08-20 7:30 ` [PATCH 6/9] locking/lockdep: Cleanup Peter Zijlstra
2020-08-20 7:30 ` [PATCH 7/9] nds32: Implement arch_irqs_disabled() Peter Zijlstra
2020-08-20 7:30 ` [PATCH 8/9] lockdep: Only trace IRQ edges Peter Zijlstra
2020-08-20 7:30 ` [PATCH 9/9] lockdep,trace: Expose tracepoints Peter Zijlstra
2020-08-20 14:36 ` [PATCH 0/9] TRACE_IRQFLAGS wreckage Steven Rostedt
2020-08-20 14:39 ` Steven Rostedt
2020-08-20 14:49 ` Marco Elver
2020-08-20 14:58 ` peterz [this message]
2020-08-20 16:53 ` Steven Rostedt
2020-08-20 17:20 ` Marco Elver
2020-08-20 19:59 ` Steven Rostedt
2020-08-21 6:37 ` Marco Elver
2020-08-21 6:54 ` peterz
2020-08-21 7:05 ` Marco Elver
2020-08-27 7:54 ` [tip: sched/urgent] sched: Use __always_inline on is_idle_task() tip-bot2 for Marco Elver
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