Viresh Kumar <viresh.kumar@xxxxxxxxxx> writes:
> On 6 January 2014 14:31, Bjørn Mork <bjorn@xxxxxxx> wrote:
>> That's correct. I have not observed this on suspend to RAM. But then
>> again I haven't rigged any way to log that, so I don't think it's
>> conclusive..
>>
>> The point I tried to make is that it isn't related to any hibernation
>> *failures*. The warning appears even if the add_dev() is successful,
>> and it also appears if I touch only the *boot* cpu cpufreq attributes.
>
> Okay.. But your log below is for add_dev() failure case.
Any suggestion on how to capure warnings issued between freeze and thaw
is appreciated :-)
Will a netconsole work? I can try that later.
>> I.e., this seems to be unrelated to the hotplugging code.
>>
>> Here's another copy of the warning, captured by cancelling hibernation
>> as I don't have any other way to log it at the moment. But I do see the
>> warning appear on the console *before* cancelling. And I also see this
>> warning appear when trying the in-kernel hibernation instead of
>> userspace.
>
> How do you cancel hibernation here? Sorry, what is in-kernel hibernation?
I don't know the proper terms here. I normally use s2disk from uswsusp
to hibernate. By "in-kernel hibernation" I meant the process initiated
by doing
echo disk >/sys/power/state
>> [ 267.893084] ======================================================
>> [ 267.893085] [ INFO: possible circular locking dependency detected ]
>> [ 267.893087] 3.13.0-rc6+ #183 Tainted: G W
>> [ 267.893089] -------------------------------------------------------
>> [ 267.893090] s2disk/5450 is trying to acquire lock:
>> [ 267.893101] (s_active#164){++++.+}, at: [<ffffffff8118b9d7>] sysfs_addrm_finish+0x28/0x46
>> [ 267.893102]
>> [ 267.893102] but task is already holding lock:
>> [ 267.893111] (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff81039ff5>] cpu_hotplug_begin+0x28/0x50
>> [ 267.893112]
>> [ 267.893112] which lock already depends on the new lock.
>> [ 267.893112]
>> [ 267.893113]
>> [ 267.893113] the existing dependency chain (in reverse order) is:
>> [ 267.893117]
>> [ 267.893117] -> #1 (cpu_hotplug.lock){+.+.+.}:
>> [ 267.893123] [<ffffffff81075027>] lock_acquire+0xfb/0x144
>> [ 267.893128] [<ffffffff8139d4d2>] mutex_lock_nested+0x6c/0x397
>> [ 267.893132] [<ffffffff81039f4a>] get_online_cpus+0x3c/0x50
>> [ 267.893137] [<ffffffff812a69c4>] store+0x20/0xad
>> [ 267.893142] [<ffffffff8118a9a1>] sysfs_write_file+0x138/0x18b
>> [ 267.893147] [<ffffffff8112a428>] vfs_write+0x9c/0x102
>> [ 267.893151] [<ffffffff8112a716>] SyS_write+0x50/0x85
>> [ 267.893155] [<ffffffff813a57a2>] system_call_fastpath+0x16/0x1b
>> [ 267.893160]
>> [ 267.893160] -> #0 (s_active#164){++++.+}:
>> [ 267.893164] [<ffffffff81074760>] __lock_acquire+0xae3/0xe68
>> [ 267.893168] [<ffffffff81075027>] lock_acquire+0xfb/0x144
>> [ 267.893172] [<ffffffff8118b027>] sysfs_deactivate+0xa5/0x108
>> [ 267.893175] [<ffffffff8118b9d7>] sysfs_addrm_finish+0x28/0x46
>> [ 267.893178] [<ffffffff8118bd3f>] sysfs_remove+0x2a/0x31
>> [ 267.893182] [<ffffffff8118be2f>] sysfs_remove_dir+0x66/0x6b
>> [ 267.893186] [<ffffffff811d5d11>] kobject_del+0x18/0x42
>> [ 267.893190] [<ffffffff811d5e1c>] kobject_cleanup+0xe1/0x14f
>> [ 267.893193] [<ffffffff811d5ede>] kobject_put+0x45/0x49
>> [ 267.893197] [<ffffffff812a6ed5>] cpufreq_policy_put_kobj+0x37/0x83
>
> All above is for case where add dev was required to clear up earlier
> allocated policy as something failed during add_dev()
I see. I'll try capturing at least part of the warning with a camera,
when it's not failing.
>> [ 267.893201] [<ffffffff812a8bfb>] __cpufreq_add_dev.isra.18+0x75e/0x78c
>> [ 267.893204] [<ffffffff812a8c89>] cpufreq_cpu_callback+0x53/0x88
>> [ 267.893208] [<ffffffff813a314c>] notifier_call_chain+0x67/0x92
>> [ 267.893213] [<ffffffff8105bce4>] __raw_notifier_call_chain+0x9/0xb
>> [ 267.893217] [<ffffffff81039e7c>] __cpu_notify+0x1b/0x32
>> [ 267.893221] [<ffffffff81039ea1>] cpu_notify+0xe/0x10
>> [ 267.893225] [<ffffffff8103a12b>] _cpu_up+0xf1/0x124
>> [ 267.893230] [<ffffffff8138ee7d>] enable_nonboot_cpus+0x52/0xbf
>> [ 267.893234] [<ffffffff8107a2a3>] hibernation_snapshot+0x1be/0x2ed
>
> And this is again the same log as what you have sent last time. It happened
> while saving image after disabling all non-boot CPUs. And so it happened for
> your case as your driver->init() was failing, so it may not get reproduced at
> my end. Haven't tried it though.
>
>> I don't think I do anything extra-ordinary to trigger this, so I would
>> be surprised if you can't reproduce it by doing
>>
>> export x=`cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor`
>> echo $x >/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
>> s2disk
>
> I don't see you cancelling hibernation here. Sorry got confused on how
> exactly you reproduced it.
I cancelled by pressing backspace while the image was being written.
Bjørn
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