Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755620AbbESJif (ORCPT ); Tue, 19 May 2015 05:38:35 -0400 Received: from mail-ob0-f174.google.com ([209.85.214.174]:33095 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755565AbbESJi3 (ORCPT ); Tue, 19 May 2015 05:38:29 -0400 MIME-Version: 1.0 In-Reply-To: <5559FCC0.2050302@linaro.org> References: <5559FCC0.2050302@linaro.org> Date: Tue, 19 May 2015 11:38:28 +0200 X-Google-Sender-Auth: LLLT8PCY_6T7uSorP6QIystDLH0 Message-ID: Subject: Re: Calling irq_set_irq_wake() from .set_irq_wake()? From: Geert Uytterhoeven To: "Grygorii.Strashko@linaro.org" , Roger Quadros Cc: Thomas Gleixner , Ingo Molnar , Linus Walleij , Alexandre Courbot , "linux-gpio@vger.kernel.org" , "linux-omap@vger.kernel.org" , "linux-kernel@vger.kernel.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: 4597 Lines: 117 Hi Grygorii, 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 ;-) gpiochip_irq_map: setting lockdep class for irq 111 gpiochip_irq_map: setting lockdep class for irq 112 gpiochip_irq_map: setting lockdep class for irq 113 gpiochip_irq_map: setting lockdep class for irq 114 gpiochip_irq_map: setting lockdep class for irq 115 gpiochip_irq_map: setting lockdep class for irq 116 gpiochip_irq_map: setting lockdep class for irq 117 gpiochip_irq_map: setting lockdep class for irq 118 gpiochip_irq_map: setting lockdep class for irq 119 gpiochip_irq_map: setting lockdep class for irq 120 gpiochip_irq_map: setting lockdep class for irq 121 gpiochip_irq_map: setting lockdep class for irq 122 gpiochip_irq_map: setting lockdep class for irq 123 gpiochip_irq_map: setting lockdep class for irq 124 gpiochip_irq_map: setting lockdep class for irq 125 gpiochip_irq_map: setting lockdep class for irq 126 pcf857x_irq_set_wake: setting wake for irq 96 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! >>>>> 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. 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/