From: Thomas Gleixner <tglx@linutronix.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jesse Brandeburg <jesse.brandeburg@intel.com>,
Arjan van de Ven <arjan@infradead.org>
Subject: Re: [regression] Latest git has WARN_ON storm with e1000e driver
Date: Fri, 3 Oct 2008 21:41:06 +0200 (CEST) [thread overview]
Message-ID: <alpine.LFD.2.00.0810032139100.4573@apollo> (raw)
In-Reply-To: <alpine.LFD.2.00.0810030901170.3185@nehalem.linux-foundation.org>
On Fri, 3 Oct 2008, Linus Torvalds wrote:
> On Fri, 3 Oct 2008, Christian Borntraeger wrote:
> >
> > kernel_init does lock_kernel (which does preempt_disable).
> > The kernel_unlock is done in init_post. As far as I can see, this happens
> > after the driver init calls.
>
> Yes. I just came to the same conclusion: preempt_count is 1 already in
> do_one_initcall().
>
> So this whole bug is actually because that debug test is just _broken_. It
> shouldn't be WARN_ON(preempt_count()), it should be 'might_sleep()', which
> does it right.
>
> The right thing to check is "in_atomic() || irqs_disabled()".
>
> Duh. That was wasted effort for a buggy test.
Stupid me. Yes I should have used might_sleep. It just did not trigger
here as I did not have the driver compiled into the kernel.
Sorry,
tglx
next prev parent reply other threads:[~2008-10-03 19:43 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-03 8:41 [regression] Latest git has WARN_ON storm with e1000e driver Christian Borntraeger
2008-10-03 14:52 ` Linus Torvalds
2008-10-03 15:20 ` Christian Borntraeger
2008-10-03 15:36 ` Linus Torvalds
2008-10-03 15:50 ` Christian Borntraeger
2008-10-03 15:55 ` Christian Borntraeger
2008-10-03 16:05 ` Linus Torvalds
2008-10-03 16:23 ` Linus Torvalds
2008-10-03 16:25 ` Brandeburg, Jesse
2008-10-03 16:36 ` Linus Torvalds
2008-10-03 19:41 ` Thomas Gleixner [this message]
2008-10-03 16:25 ` Christian Borntraeger
2008-10-03 15:08 ` Arjan van de Ven
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