On 05/18/2015 05:31 PM, Thomas Gleixner wrote:
> On Sun, 17 May 2015, Geert Uytterhoeven wrote:
>>>>> At least the recursive locking message no longer appears after the revert.
>>>>>
>>>>> [ 30.591905] PM: Syncing filesystems ... done.
>>>>> [ 30.623060] Freezing user space processes ... (elapsed 0.003 seconds) done.
>>>>> [ 30.634470] Freezing remaining freezable tasks ... (elapsed 0.002 seconds) done.
>>>>> [ 30.658288] sd 0:0:0:0: [sda] Synchronizing SCSI cache
>>>>> [ 30.663678]
>>>>> [ 30.663681] =============================================
>>>>> [ 30.663683] [ INFO: possible recursive locking detected ]
>>>>> [ 30.663688] 4.1.0-rc3 #1115 Not tainted
>>>>> [ 30.663693] ---------------------------------------------
>>>>> [ 30.663697] suspend.sh/2319 is trying to acquire lock:
>>>>> [ 30.663719] (class){......}, at: [<c0096ebc>] __irq_get_desc_lock+0x48/0x88
>>>>> [ 30.663722]
>>>>> [ 30.663722] but task is already holding lock:
>>>>> [ 30.663734] (class){......}, at: [<c0096ebc>] __irq_get_desc_lock+0x48/0x88
>>>>
>>>> Does this mean .set_irq_wake() cannot call irq_set_irq_wake()?
>
> It can call it, if it's guaranteed that this wont deadlock.
>
> To tell lockdep that you sure about that, you need to set a different
> lock class for the child interrupts. irq_set_lockdep_class() is what
> you want to use here.
Hm. Seems we already have corresponding call in gpiochip_irq_map:
static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hwirq)
{
struct gpio_chip *chip = d->host_data;
irq_set_chip_data(irq, chip);
irq_set_lockdep_class(irq, &gpiochip_irq_lock_class);
^^^^
commit e45d1c80c0eee88e82751461e9cac49d9ed287bc
Author: Linus Walleij <linus.walleij@xxxxxxxxxx>
Date: Tue Apr 22 14:01:46 2014 +0200
gpio: put GPIO IRQs into their own lock clas
added in Kernel v3.16
Roger, can you confirm that you've observed this issue with latest kernel, pls?
>
>>>> Many GPIO drivers do that, as they need to propagate wake-up state to the
>>>> parent interrupt controller?
>>>
>>> As I remember, there was similar problem, so I found corresponding patch (just FYI)
>>>
>>> ab2b926 mfd: Fix twl6030 lockdep recursion warning on setting wake IRQs
>>>
>>> Not sure such kind of solution is the best choice (
>>
>> That looks like a convoluted solution...
>
> Indeed. See above.
--
regards,
-grygorii
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