Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752413AbbFFIQ7 (ORCPT ); Sat, 6 Jun 2015 04:16:59 -0400 Received: from mail-ob0-f171.google.com ([209.85.214.171]:36278 "EHLO mail-ob0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750952AbbFFIQs (ORCPT ); Sat, 6 Jun 2015 04:16:48 -0400 MIME-Version: 1.0 In-Reply-To: <55717023.2090908@ti.com> References: <5559FCC0.2050302@linaro.org> <556F5B0F.7040603@ti.com> <20150605053543.3b10d605@rockdesk> <55717023.2090908@ti.com> Date: Sat, 6 Jun 2015 10:16:47 +0200 X-Google-Sender-Auth: FOBIaiGoNHMN3KYDYyHYXgn-8o4 Message-ID: Subject: Re: Calling irq_set_irq_wake() from .set_irq_wake()? From: Geert Uytterhoeven To: Grygorii Strashko Cc: Roger Quadros , Linus Walleij , Alexandre Courbot , Thomas Gleixner , Ingo Molnar , "linux-gpio@vger.kernel.org" , "linux-omap@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "Grygorii.Strashko@linaro.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4977 Lines: 123 On Fri, Jun 5, 2015 at 11:47 AM, Grygorii Strashko wrote: > On 06/05/2015 05:35 AM, Roger Quadros wrote: >> On Wed, 3 Jun 2015 22:52:47 +0300 >> Grygorii Strashko wrote: >>> On 05/19/2015 12:38 PM, Geert Uytterhoeven wrote: >>>> On Mon, May 18, 2015 at 4:52 PM, Grygorii.Strashko@linaro.org >>>> wrote: >>>>> 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: [] __irq_get_desc_lock+0x48/0x88 >>>>>>>>>> [ 30.663722] >>>>>>>>>> [ 30.663722] but task is already holding lock: >>>>>>>>>> [ 30.663734] (class){......}, at: [] __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); >>>>> ^^^^ >>>> >>>> That piece of code sets the lockdep class of the gpiochip's interrupts, not >>>> the parent interrupt. >>>> >>>> Found out the hard way by adding some debug code ;-) >>> [..] >>>> >>>> However, I cannot reproduce the problem on sh73a0/kzm9g with >>>> s2ram on a current tree (renesas-drivers-2015-05-19-v4.1-rc4 from >>>> (https://git.kernel.org/cgit/linux/kernel/git/geert/renesas-drivers.git), using >>>> >>>> CONFIG_LOCKDEP_SUPPORT=y >>>> CONFIG_LOCKDEP=y >>>> CONFIG_DEBUG_LOCKDEP=y >>>> CONFIG_PROVE_LOCKING=y >>>> >>>> Wake-up from gpio-keys works fine, no scary messages. >>>> >>>>> commit e45d1c80c0eee88e82751461e9cac49d9ed287bc >>>>> Author: Linus Walleij >>>>> 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? >>>> >>>> Yes please. Thanks! >> >> Issue is reproducible on v4.1-rc6 >> >>> >>> Unfortunately, I was able to reproduce it, but have no clue how to fix it gracefully. >>> lockdep_set_class_and_subclass(..,gpio_chip->base)? >>> >>> HW configuration which generates lockdep warning: >>> >>> [SOC GPIO bankA.gpioX] <- irq - [pcf875x.gpioY] <- irq - DevZ.enable_irq_wake(pcf_gpioY_irq); >>> >>> There stacked GPIO chips, but gpiolib uses only one lockdep class for all GPIOirqchips - >>> - gpiochip_irq_lock_class. >> >> If this is a gpiolib core issue are we (dra7-evm) the only stacked GPIO users facing >> this problem? >> >> Linus/Alexandre/Geert, >> >> Please advise what can be done for v4.1. The warning is annoying for dra7-evm users. >> Should we temporarily revert the patch even though it is correct and add it back when the >> gpiolib core issue is fixed? > > No. Pls. don't do that. See https://lkml.org/lkml/2015/6/3/965 I'm about to leave for a business trip to Japan. I will give it a try when I'm back home. > Simple revert is not good solution. > > Probably we need to allow GPIO drivers to specify own lockdep class somehow. Indeed. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/