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Date:   Tue, 26 Jul 2022 13:50:06 +0100
From:   Mark Rutland <mark.rutland@arm.com>
To:     Sudeep Holla <sudeep.holla@arm.com>
Cc:     linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        Peter Zijlstra <peterz@infradead.org>
Subject: Re: [-next] Lockdep warnings
Message-ID: <Yt/i/o3Sb+niH2e+@FVFF77S0Q05N>
References: <20220726104134.3b3awfphvafljdgp@bogus>
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On Tue, Jul 26, 2022 at 01:40:40PM +0100, Mark Rutland wrote:
> [Adding Peter; I suspect this is due to the cpuidle rework]

Looking again I see the cpuidle rework isn't in next, so evidently not...

Sorry for the noise!

Mark.

> 
> I'll go give next a spin in a VM, but I suspect I might need real HW to see
> this due to the way PSCI idle states work.
> 
> Mark.
> 
> On Tue, Jul 26, 2022 at 11:41:34AM +0100, Sudeep Holla wrote:
> > I was seeing the below lockdep warnings on my arm64 Juno development
> > platform almost 2 weeks back with -next. I wanted to check for similar
> > reports before post and forgot.
> > 
> > --->8
> > 
> > DEBUG_LOCKS_WARN_ON(lockdep_hardirqs_enabled())
> >  hardirqs last  enabled at (46157): cpuidle_enter_state+0x174/0x2b4
> >  WARNING: CPU: 5 PID: 0 at kernel/locking/lockdep.c:5506 check_flags+0x90/0x1e8
> >  hardirqs last disabled at (46158): el1_interrupt+0x2c/0xc8
> >  Modules linked in:
> >  softirqs last  enabled at (46154): __do_softirq+0x2c0/0x388
> >  softirqs last disabled at (46139): __irq_exit_rcu+0x118/0x18c
> >  CPU: 5 PID: 0 Comm: swapper/5 Not tainted 5.19.0-rc6-next-20220714 #9
> >  pstate: 600000c5 (nZCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> >  pc : check_flags+0x90/0x1e8
> >  lr : check_flags+0x90/0x1e8
> >  Call trace:
> >   check_flags+0x90/0x1e8
> >   lock_is_held_type+0x80/0x164
> >   rcu_read_lock_sched_held+0x40/0x7c
> >   trace_rcu_dyntick+0x5c/0x140
> >   ct_kernel_enter+0x78/0xd4
> >   ct_idle_exit+0x1c/0x44
> >   cpu_idle_poll+0x74/0xb8
> >   do_idle+0x90/0x2c4
> >   cpu_startup_entry+0x30/0x34
> >   secondary_start_kernel+0x130/0x144
> >   __secondary_switched+0xb0/0xb4
> >  irq event stamp: 64229
> >  hardirqs last  enabled at (64229): cpu_idle_poll+0x40/0xb8
> >  hardirqs last disabled at (64228): do_idle+0xbc/0x2c4
> >  softirqs last  enabled at (64190): __do_softirq+0x2c0/0x388
> >  softirqs last disabled at (64185): __irq_exit_rcu+0x118/0x18c
> >  ---[ end trace 0000000000000000 ]---
> >  possible reason: unannotated irqs-off.
> >  irq event stamp: 64229
> >  hardirqs last  enabled at (64229): cpu_idle_poll+0x40/0xb8
> >  hardirqs last disabled at (64228): do_idle+0xbc/0x2c4
> >  softirqs last  enabled at (64190): __do_softirq+0x2c0/0x388
> >  softirqs last disabled at (64185): __irq_exit_rcu+0x118/0x18c
> > 
> > ----
> > 
> > However I don't see the above warning with the latest -next. When I tried
> > yesterday's -next now, I see a different warning. Not sure if they are
> > related. I haven't tried to bisect.
> > 
> > --->8
> > =============================
> > [ BUG: Invalid wait context ]
> > 5.19.0-rc8-next-20220725 #38 Not tainted
> > -----------------------------
> > swapper/0/0 is trying to lock:
> > (&drvdata->spinlock){....}-{3:3}, at: cti_cpu_pm_notify+0x54/0x114
> > other info that might help us debug this:
> > context-{5:5}
> > 1 lock held by swapper/0/0:
> >  #0: (cpu_pm_notifier.lock){....}-{2:2}, at: cpu_pm_enter+0x2c/0x80
> > stack backtrace:
> > CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.19.0-rc8-next-20220725-00004-g599e6691ed8c #38
> > Call trace:
> >  dump_backtrace+0xe8/0x108
> >  show_stack+0x18/0x4c
> >  dump_stack_lvl+0x90/0xc8
> >  dump_stack+0x18/0x54
> >  __lock_acquire+0xa70/0x32d0
> >  lock_acquire+0x160/0x308
> >  _raw_spin_lock+0x60/0xa0
> >  cti_cpu_pm_notify+0x54/0x114
> >  raw_notifier_call_chain_robust+0x50/0xd4
> >  cpu_pm_enter+0x48/0x80
> >  psci_enter_idle_state+0x34/0x74
> >  cpuidle_enter_state+0x120/0x2a8
> >  cpuidle_enter+0x38/0x50
> >  do_idle+0x1e8/0x2b8
> >  cpu_startup_entry+0x24/0x28
> >  kernel_init+0x0/0x1a0
> >  start_kernel+0x0/0x470
> >  start_kernel+0x34c/0x470
> >  __primary_switched+0xbc/0xc4
> > 
> > ----
> > 
> > --
> > Regards,
> > Sudeep