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From: Richard Weinberger <richard@nod.at>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: peterz@infradead.org, hpa@zytor.com, mingo@elte.hu,
	linux-kernel@vger.kernel.org, linux-next@vger.kernel.org
Subject: Re: linux-next: User Mode Linux broken
Date: Fri, 22 Oct 2010 12:50:49 +0200	[thread overview]
Message-ID: <ed248baebfad9b050f53a6832435a9a5@radon2.swed.at> (raw)
In-Reply-To: <alpine.LFD.2.00.1010220900230.3467@localhost6.localdomain6>

On Fri, 22 Oct 2010 09:03:44 +0200 (CEST), Thomas Gleixner
<tglx@linutronix.de> wrote:
> On Thu, 21 Oct 2010, Richard Weinberger wrote:
>> Am Donnerstag 21 Oktober 2010, 21:45:35 schrieb Thomas Gleixner:
>> > Why shold it solve it ? irq_enable is set to compat_irq_enable which
>> > in turn calls chip->enable.
>> >
>> > So how's that different ?
>>
>> I took a closer look on the issue.
>>
>> check_irq_resend() gets called before irq_chip_set_defaults().
>> In the first call to check_irq_resend() desc->irq_data.chip->irq_enable is
>> NULL. UML dies due to a NULL-pointer dereference...
>>
>> I don't know why check_irq_resend() is called before irq_chip_set_defaults().
>> It's your code. ;-)
> 
> Well, but it only gets called via enable_irq(). So that means
> something is calling enable_irq _before_ request/setup_irq().
> 
> arch/um/kernel/irq.c:init_IRQ() does that :)

Sorry I'm not very familiar with the IRQ stuff.
Does that mean init_IRQ() is not allowed to call enable_irq()?

Thanks,
//richard

> Thanks,
> 
> 	tglx

  reply	other threads:[~2010-10-22 10:50 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-21 11:15 linux-next: User Mode Linux broken Richard Weinberger
2010-10-21 16:09 ` Thomas Gleixner
2010-10-21 19:22   ` Richard Weinberger
2010-10-21 19:45     ` Thomas Gleixner
2010-10-21 20:27       ` Richard Weinberger
2010-10-22  7:03         ` Thomas Gleixner
2010-10-22 10:50           ` Richard Weinberger [this message]
2010-10-22 11:12             ` Thomas Gleixner
2010-10-22 13:27               ` Thomas Gleixner

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