Re: [LOCKDEP] cpufreq: possible circular locking dependency detected

["Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>]

On 07/16/2013 04:14 PM, Sergey Senozhatsky wrote:
> On (07/16/13 14:03), Srivatsa S. Bhat wrote:
>>>> So here is the solution:
>>>>
>>>> On 3.11-rc1, apply these patches in the order mentioned below, and check
>>>> whether it fixes _all_ problems (both the warnings about IPI as well as the
>>>> lockdep splat).
>>>>
>>>> 1. Patch given in:  https://lkml.org/lkml/2013/7/11/661
>>>>    (Just apply patch 1, not the entire patchset).
>>>>
>>>> 2. Apply the patch shown below, on top of the above patch:
>>>>
>>>> ---------------------------------------------------------------------------
>>>>
>>>
>>> Hello Srivatsa,
>>> Thanks, I'll test a bit later -- in the morning. (laptop stopped resuming from
>>> suspend, probably radeon dmp).
>>>
>>>
>>
>> Sure, thanks!
>>
>>>
>>> Shouldn't we also kick the console lock?
>>>
>>>
>>>  kernel/printk.c | 3 +++
>>>  1 file changed, 3 insertions(+)
>>>
>>> diff --git a/kernel/printk.c b/kernel/printk.c
>>> index d37d45c..3e20233 100644
>>> --- a/kernel/printk.c
>>> +++ b/kernel/printk.c
>>> @@ -1926,8 +1926,11 @@ static int __cpuinit console_cpu_notify(struct notifier_block *self,
>>>  {
>>>  	switch (action) {
>>>  	case CPU_ONLINE:
>>> +	case CPU_ONLINE_FROZEN:
>>>  	case CPU_DEAD:
>>> +	case CPU_DEAD_FROZEN:
>>>  	case CPU_DOWN_FAILED:
>>> +	case CPU_DOWN_FAILED_FROZEN:
>>>  	case CPU_UP_CANCELED:
>>>  		console_lock();
>>>  		console_unlock();
>>>
>>>
>>
>> No need. suspend_console() and resume_console() already handle it
>> properly in the suspend/resume case, from what I can see.
>>
> 
> I've managed to wake up my laptop from suspend, and something's not right.
> 
> 
> 	# for i in {1..5}; do \
> 	echo 0 > /sys/devices/system/cpu/cpu3/online; \
> 	echo 0 > /sys/devices/system/cpu/cpu2/online; \
> 	echo 1 > /sys/devices/system/cpu/cpu3/online; \
> 	echo 0 > /sys/devices/system/cpu/cpu1/online; \
> 	echo 1 > /sys/devices/system/cpu/cpu1/online; \
> 	echo 1 > /sys/devices/system/cpu/cpu2/online; \
> 	done
> 	# systemctl suspend
> 	->	resume
> 
> 
> [  227.329656] ACPI: Preparing to enter system sleep state S3
> [  227.353334] PM: Saving platform NVS memory
> 
> [  227.355403] ======================================================
> [  227.355404] [ INFO: possible circular locking dependency detected ]
> [  227.355407] 3.11.0-rc1-dbg-01398-gf537e41-dirty #1838 Not tainted
> [  227.355408] -------------------------------------------------------
> [  227.355411] systemd-sleep/2280 is trying to acquire lock:
> [  227.355426]  (cpu_add_remove_lock){+.+.+.}, at: [<ffffffff8104dab4>]
> disable_nonboot_cpus+0x24/0x120
> [  227.355427] 
> but task is already holding lock:
> [  227.355434]  (console_lock){+.+.+.}, at: [<ffffffff8104c956>]
> suspend_console+0x26/0x40
> [  227.355435] 
> which lock already depends on the new lock.
> 
> [  227.355436] 
> the existing dependency chain (in reverse order) is:
> [  227.355441] 
> -> #2 (console_lock){+.+.+.}:
> [  227.355448]        [<ffffffff810b8fb4>] lock_acquire+0xa4/0x200
> [  227.355452]        [<ffffffff8104b197>] console_lock+0x77/0x80
> [  227.355456]        [<ffffffff8104cf91>] console_cpu_notify+0x31/0x40
> [  227.355462]        [<ffffffff8107cd6d>] notifier_call_chain+0x5d/0x110
> [  227.355466]        [<ffffffff8107ce2e>] __raw_notifier_call_chain+0xe/0x10
> [  227.355469]        [<ffffffff8104d5a3>] cpu_notify+0x23/0x50
> [  227.355473]        [<ffffffff8104d5de>] cpu_notify_nofail+0xe/0x20
> [  227.355482]        [<ffffffff815fafad>] _cpu_down+0x1ad/0x330
> [  227.355486]        [<ffffffff815fb166>] cpu_down+0x36/0x50
> [  227.355493]        [<ffffffff814ad8cd>] cpu_subsys_offline+0x1d/0x30
> [  227.355498]        [<ffffffff814a8de5>] device_offline+0x95/0xc0
> [  227.355502]        [<ffffffff814a8ee2>] store_online+0x42/0x90
> [  227.355506]        [<ffffffff814a64f8>] dev_attr_store+0x18/0x30
> [  227.355513]        [<ffffffff811ec71b>] sysfs_write_file+0xdb/0x150
> [  227.355517]        [<ffffffff8117a68d>] vfs_write+0xbd/0x1e0
> [  227.355522]        [<ffffffff8117ad7c>] SyS_write+0x4c/0xa0
> [  227.355527]        [<ffffffff8160cbfe>] tracesys+0xd0/0xd5
> [  227.355531] 
> -> #1 (cpu_hotplug.lock){+.+.+.}:
> [  227.355535]        [<ffffffff810b8fb4>] lock_acquire+0xa4/0x200
> [  227.355541]        [<ffffffff81605b47>] mutex_lock_nested+0x67/0x410
> [  227.355545]        [<ffffffff8104d54b>] cpu_hotplug_begin+0x2b/0x60
> [  227.355549]        [<ffffffff8104d61a>] _cpu_up+0x2a/0x170
> [  227.355552]        [<ffffffff8104d7b9>] cpu_up+0x59/0x80
> [  227.355558]        [<ffffffff81cf51b6>] smp_init+0x64/0x95
> [  227.355566]        [<ffffffff81cdaf21>] kernel_init_freeable+0x84/0x191
> [  227.355570]        [<ffffffff815fa34e>] kernel_init+0xe/0x180
> [  227.355574]        [<ffffffff8160c9ac>] ret_from_fork+0x7c/0xb0
> [  227.355578] 
> -> #0 (cpu_add_remove_lock){+.+.+.}:
> [  227.355582]        [<ffffffff810b8106>] __lock_acquire+0x1766/0x1d30
> [  227.355586]        [<ffffffff810b8fb4>] lock_acquire+0xa4/0x200
> [  227.355590]        [<ffffffff81605b47>] mutex_lock_nested+0x67/0x410
> [  227.355594]        [<ffffffff8104dab4>] disable_nonboot_cpus+0x24/0x120
> [  227.355601]        [<ffffffff810a0973>] suspend_devices_and_enter+0x1f3/0x680
> [  227.355605]        [<ffffffff810a0fd2>] pm_suspend+0x1d2/0x240
> [  227.355609]        [<ffffffff8109fa19>] state_store+0x79/0xf0
> [  227.355614]        [<ffffffff81312dbf>] kobj_attr_store+0xf/0x20
> [  227.355618]        [<ffffffff811ec71b>] sysfs_write_file+0xdb/0x150
> [  227.355621]        [<ffffffff8117a68d>] vfs_write+0xbd/0x1e0
> [  227.355624]        [<ffffffff8117ad7c>] SyS_write+0x4c/0xa0
> [  227.355628]        [<ffffffff8160cbfe>] tracesys+0xd0/0xd5
> [  227.355629] 
> other info that might help us debug this:
> 
> [  227.355635] Chain exists of:
>   cpu_add_remove_lock --> cpu_hotplug.lock --> console_lock
> 
>   [  227.355637]  Possible unsafe locking scenario:
> 
>   [  227.355638]        CPU0                    CPU1
>   [  227.355639]        ----                    ----
>   [  227.355642]   lock(console_lock);
>   [  227.355644]                                lock(cpu_hotplug.lock);
>   [  227.355647]                                lock(console_lock);
>   [  227.355650]   lock(cpu_add_remove_lock);
>   [  227.355651] 
>    *** DEADLOCK ***
> 
>    [  227.355653] 5 locks held by systemd-sleep/2280:
>    [  227.355661]  #0:  (sb_writers#6){.+.+.+}, at: [<ffffffff8117a78b>]   vfs_write+0x1bb/0x1e0
>    [  227.355668]  #1:  (&buffer->mutex){+.+.+.}, at:   [<ffffffff811ec67c>] sysfs_write_file+0x3c/0x150
>    [  227.355676]  #2:  (s_active#110){.+.+.+}, at: [<ffffffff811ec703>]   sysfs_write_file+0xc3/0x150
>    [  227.355683]  #3:  (pm_mutex){+.+.+.}, at: [<ffffffff810a0e32>]   pm_suspend+0x32/0x240
>    [  227.355690]  #4:  (console_lock){+.+.+.}, at: [<ffffffff8104c956>]   suspend_console+0x26/0x40
>    [  227.355691] 
>    stack backtrace:
>    [  227.355695] CPU: 0 PID: 2280 Comm: systemd-sleep Not tainted   3.11.0-rc1-dbg-01398-gf537e41-dirty #1838
>    [  227.355697] Hardware name: Acer             Aspire 5741G   /Aspire 5741G    , BIOS V1.20 02/08/2011
>    [  227.355703]  ffffffff82208680 ffff88015151bbc8 ffffffff81603038   ffffffff822073f0
>    [  227.355707]  ffff88015151bc08 ffffffff815ffdaa ffff880153389fa0   ffff88015338a788
>    [  227.355712]  1d81e4832c04c441 ffff88015338a760 ffff88015338a788   ffff880153389fa0
>    [  227.355713] Call Trace:
>    [  227.355719]  [<ffffffff81603038>] dump_stack+0x4e/0x82
>    [  227.355723]  [<ffffffff815ffdaa>] print_circular_bug+0x2b6/0x2c5
>    [  227.355727]  [<ffffffff810b8106>] __lock_acquire+0x1766/0x1d30
>    [  227.355733]  [<ffffffff81054aec>] ?   walk_system_ram_range+0x5c/0x140
>    [  227.355737]  [<ffffffff810b63f4>] ? mark_held_locks+0x94/0x140
>    [  227.355741]  [<ffffffff810b8fb4>] lock_acquire+0xa4/0x200
>    [  227.355745]  [<ffffffff8104dab4>] ?   disable_nonboot_cpus+0x24/0x120
>    [  227.355749]  [<ffffffff8104dab4>] ?   disable_nonboot_cpus+0x24/0x120
>    [  227.355753]  [<ffffffff81605b47>] mutex_lock_nested+0x67/0x410
>    [  227.355757]  [<ffffffff8104dab4>] ?   disable_nonboot_cpus+0x24/0x120
>    [  227.355761]  [<ffffffff81607e9e>] ? mutex_unlock+0xe/0x10
>    [  227.355768]  [<ffffffff8135bd2f>] ? acpi_os_get_iomem+0x4c/0x54
>    [  227.355772]  [<ffffffff8104dab4>] disable_nonboot_cpus+0x24/0x120
>    [  227.355777]  [<ffffffff810a0973>]   suspend_devices_and_enter+0x1f3/0x680
>    [  227.355780]  [<ffffffff815fefc6>] ? printk+0x67/0x69
>    [  227.355785]  [<ffffffff810a0fd2>] pm_suspend+0x1d2/0x240
>    [  227.355789]  [<ffffffff8109fa19>] state_store+0x79/0xf0
>    [  227.355792]  [<ffffffff81312dbf>] kobj_attr_store+0xf/0x20
>    [  227.355796]  [<ffffffff811ec71b>] sysfs_write_file+0xdb/0x150
>    [  227.355799]  [<ffffffff8117a68d>] vfs_write+0xbd/0x1e0
>    [  227.355804]  [<ffffffff81198490>] ? fget_light+0x320/0x4b0
>    [  227.355808]  [<ffffffff8117ad7c>] SyS_write+0x4c/0xa0
>    [  227.355811]  [<ffffffff8160cbfe>] tracesys+0xd0/0xd5
>    [  227.355814] Disabling non-boot CPUs ...
>    [  227.357731] smpboot: CPU 1 is now offline
>    [  227.461072] smpboot: CPU 2 is now offline
>    [  227.565119] smpboot: CPU 3 is now offline
> 
>

This also looks like a different issue altogether, and IMHO deserves
attention in a separate, dedicated email thread. Can you post it in a
new thread please?

Also, since you didn't get the original lockdep warning you reported,
and since you didn't hit the IPI-to-offline-cpus warnings as well, I
think we can safely conclude that my patches fixed your original problem.

Rafael, could you kindly pick up this second patch[2] as well (with CC
to stable)? (I'm aware that you already picked up the first one[1]).

Thanks a lot!

Regards,
Srivatsa S. Bhat

[1]. https://lkml.org/lkml/2013/7/11/661
[2]. http://marc.info/?l=linux-kernel&m=137389460805002&w=2