Re: [REGRESSION] [3.9-rc1] BUG: ktpacpi_nvramd/446 still has locks held!

[Aaron Lu <aaron.lu@intel.com>]

On 03/05/2013 03:55 AM, Maciej Rutecki wrote:
> Last known good: 3.8.0
> Bad version: 3.9-rc1
> 
> [    6.116492] =====================================
> [    6.116614] [ BUG: ktpacpi_nvramd/446 still has locks held! ]
> [    6.116737] 3.9.0-rc1 #1 Not tainted
> [    6.116821] -------------------------------------
> [    6.116900] 1 lock held by ktpacpi_nvramd/446:
> [    6.116973]  #0:  (&hotkey_thread_mutex){+.+...}, at: [<ffffffffa024e87e>] 
> hotkey_kthread+0x1f/0x354 [thinkpad_acpi]
> [    6.117193]
> [    6.117193] stack backtrace:
> [    6.117268] Pid: 446, comm: ktpacpi_nvramd Not tainted 3.9.0-rc1 #1
> [    6.117381] Call Trace:
> [    6.117445]  [<ffffffff810877ea>] debug_check_no_locks_held+0x8f/0x93
> [    6.117600]  [<ffffffff8107d8ac>] set_freezable+0x3e/0x64
> [    6.117703] input: ThinkPad Extra Buttons as 
> /devices/platform/thinkpad_acpi/input/input5
> [    6.117918]  [<ffffffffa024e890>] hotkey_kthread+0x31/0x354 [thinkpad_acpi]
> [    6.118088]  [<ffffffffa024e85f>] ? issue_volchange.29885+0x54/0x54 
> [thinkpad_acpi]
> [    6.118250]  [<ffffffff8105e296>] kthread+0xac/0xb4
> [    6.118356]  [<ffffffff8105e1ea>] ? __kthread_parkme+0x60/0x60
> [    6.118491]  [<ffffffff814b243c>] ret_from_fork+0x7c/0xb0
> [    6.118614]  [<ffffffff8105e1ea>] ? __kthread_parkme+0x60/0x60
> 
> Config:
> http://mrutecki.pl/download/kernel/3.9.0-rc1/config-3.9.0-rc1
> 
> full dmesg:
> http://mrutecki.pl/download/kernel/3.9.0-rc1/dmesg-3.9.0-rc1.txt
> 

Thanks for the report!

Looks like the following commit is related:
commit 6aa9707099c4b25700940eb3d016f16c4434360d
Author:	Mandeep Singh Baines <msb@chromium.org>  Thu Feb 28 09:03:18 2013

lockdep: check that no locks held at freeze time

And the code to trigger this problem is here:
static int hotkey_kthread(void *data)
{
	struct tp_nvram_state s[2];
	u32 poll_mask, event_mask;
	unsigned int si, so;
	unsigned long t;
	unsigned int change_detector;
	unsigned int poll_freq;
	bool was_frozen;

	mutex_lock(&hotkey_thread_mutex);

	if (tpacpi_lifecycle == TPACPI_LIFE_EXITING)
		goto exit;

	set_freezable();
~~~~~~~~~~~~~~~~~~~~~~~~~~
in thinkpad_acpi.c.

I don't know much about freeze, I've no idea what is the problem.
So Mandeep and Henrique, can you please kindly take a look? Thanks.

-Aaron