linux-kernel - Re: BUG: sleeping function called from invalid context at kernel/mutex.c

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Date:	Thu, 07 Apr 2011 13:22:26 +0800
From:	Xiaotian Feng <dfeng@...hat.com>
To:	Thomas Gleixner <tglx@...utronix.de>
CC:	LKML <linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...e.hu>,
	Venkatesh Pallipadi <venki@...gle.com>,
	Suresh Siddha <suresh.b.siddha@...el.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Peter Zijlstra <peterz@...radead.org>
Subject: Re: BUG: sleeping function called from invalid context at kernel/mutex.c

On 04/03/2011 03:12 AM, Thomas Gleixner wrote:
> On Sat, 2 Apr 2011, Xiaotian Feng wrote:
>>      I've got following warnings when I'm trying to resume from suspend, so
>> sparse_lock is not safe enough as a mutex for the suspend resume case, can
>> we simply convert sparse_lock back to spinlock?
>
> What the heck? We do not just convert a mutex to a spinlock because a
> warning triggers. And it was a mutex already in 2.6.38 w/o any such
> problems.
>
> And it is safe enough for the resume case as well, it simply cannot go
> to sleep because nothing else can hold that mutex in the early resume
> code. We take the mutex during early boot as well, but there the might
> sleep checks are disabled. And we should do the very same thing in the
> early resume code as well. Rafael, PeterZ ???
>
> But that's a different issue and not the real problem.
>
> So now instead of thinking about spinlock it would have been pretty
> simple to figure out that the warning is triggered due to commit
> d72274e5.
>
> But of course we dont want to revert d72274e5 either, though it's easy
> to figure out from the call chain that the fundamental stupidity is in
> the hpet resume code.
>
> Why the hell does it call arch_setup_hpet_msi()? That interrupt was
> completely setup _BEFORE_ we went into suspend. And I don't see any
> code which tears down the interrupt on suspend. So we run through a
> full setup for nothing. And when we have interrupt remapping enabled
> it even leaks an irte, because it allocates a new one. Utter crap.
> init_one_hpet_msi_clockevent() has the same stupid call.
>
> So no, the mutex stays a mutex and we fix crap where the crap is.
>
> The following completely untested patch should solve that. Actually we
> should be more clever and do the affinity magic in the new function as
> well, so we can get rid of this weird disable/set_affinity/enable
> hack, but that's a different story.
>

Yes, this patch resolves the warnings, thanks.

> Thanks,
>
> 	tglx
> ---
>   arch/x86/include/asm/hpet.h    |    2 ++
>   arch/x86/kernel/apic/io_apic.c |   11 +++++++++++
>   arch/x86/kernel/hpet.c         |    5 +++--
>   3 files changed, 16 insertions(+), 2 deletions(-)
>
> Index: linux-2.6/arch/x86/include/asm/hpet.h
> ===================================================================
> --- linux-2.6.orig/arch/x86/include/asm/hpet.h
> +++ linux-2.6/arch/x86/include/asm/hpet.h
> @@ -83,11 +83,13 @@ extern void hpet_msi_read(struct hpet_de
>
>   #ifdef CONFIG_PCI_MSI
>   extern int arch_setup_hpet_msi(unsigned int irq, unsigned int id);
> +extern int arch_start_hpet_msi(unsigned int irq, unsigned int id);
>   #else
>   static inline int arch_setup_hpet_msi(unsigned int irq, unsigned int id)
>   {
>   	return -EINVAL;
>   }
> +static inline int arch_start_hpet_msi(unsigned int irq, unsigned int id) { }
>   #endif
>
>   #ifdef CONFIG_HPET_EMULATE_RTC
> Index: linux-2.6/arch/x86/kernel/apic/io_apic.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/apic/io_apic.c
> +++ linux-2.6/arch/x86/kernel/apic/io_apic.c
> @@ -3477,6 +3477,17 @@ int arch_setup_hpet_msi(unsigned int irq
>   	irq_set_chip_and_handler_name(irq, chip, handle_edge_irq, "edge");
>   	return 0;
>   }
> +
> +int arch_start_hpet_msi(unsigned int irq, unsigned int id)
> +{
> +	struct msi_msg msg;
> +	int ret = msi_compose_msg(NULL, irq,&msg, id);
> +
> +	if (!ret)
> +		hpet_msi_write(irq_get_handler_data(irq),&msg);
> +	return ret;
> +}
> +
>   #endif
>
>   #endif /* CONFIG_PCI_MSI */
> Index: linux-2.6/arch/x86/kernel/hpet.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/hpet.c
> +++ linux-2.6/arch/x86/kernel/hpet.c
> @@ -370,7 +370,8 @@ static void hpet_set_mode(enum clock_eve
>   			hpet_enable_legacy_int();
>   		} else {
>   			struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
> -			hpet_setup_msi_irq(hdev->irq);
> +
> +			arch_start_hpet_msi(hdev->irq, hpet_blockid);
>   			disable_irq(hdev->irq);
>   			irq_set_affinity(hdev->irq, cpumask_of(hdev->cpu));
>   			enable_irq(hdev->irq);
> @@ -555,7 +556,7 @@ static void init_one_hpet_msi_clockevent
>   	if (!(hdev->flags&  HPET_DEV_VALID))
>   		return;
>
> -	if (hpet_setup_msi_irq(hdev->irq))
> +	if (arch_start_hpet_msi(hdev->irq, hpet_blockid))
>   		return;
>
>   	hdev->cpu = cpu;
>
>
>

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