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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Maciej Rutecki <maciej.rutecki@gmail.com>, Ingo Molnar <mingo@elte.hu>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"Rafael J. Wysocki" <rjw@sisk.pl>,
	"lenb@kernel.org" <lenb@kernel.org>,
	linux-acpi@vger.kernel.org
Subject: Re: [Linux 2.6.28-rc4] BUG: using smp_processor_id() in preemptible [00000000] code: suspend_to_disk/2934
Date: Wed, 12 Nov 2008 10:56:00 -0800 (PST)	[thread overview]
Message-ID: <alpine.LFD.2.00.0811121046360.3468@nehalem.linux-foundation.org> (raw)
In-Reply-To: <8db1092f0811121030t1977b3bbu8340b582694d1e65@mail.gmail.com>



On Wed, 12 Nov 2008, Maciej Rutecki wrote:

> -rc3 works OK
> 
> I have this bug during suspend to disk:
> 
> [  188.592151] Enabling non-boot CPUs ...
> [  188.592151] SMP alternatives: switching to SMP code
> [  188.666058] BUG: using smp_processor_id() in preemptible [00000000]
> code: suspend_to_disk/2934
> [  188.666064] caller is native_sched_clock+0x2b/0x80

The cause seems to be commit 7cbaef9c83e58bbd4bdd534b09052b6c5ec457d5, 
"sched: optimize sched_clock() a bit" by Ingo.

Which actually comments on the fact that a few callers may need to be 
updated. That wasn't good. Ingo - it's not acceptable for a latish-rc 
patch to introduce _known_ bugs and not fixing everything up.

Of course, since Maciej has frame pointers disabled, the stack trace isn't 
entirely reliable, but it looks like the problem is "init_idle()".

That thing needs to call sched_clock() with interrupts disabled. Looking 
at it, I'd also expect that it should have used "sched_clock_cpu()", but 
I'm leaving that to Ingo to sort out. Ingo?

		Linus

  reply	other threads:[~2008-11-12 18:56 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-11-12 18:30 [Linux 2.6.28-rc4] BUG: using smp_processor_id() in preemptible [00000000] code: suspend_to_disk/2934 Maciej Rutecki
2008-11-12 18:56 ` Linus Torvalds [this message]
2008-11-12 19:21   ` Ingo Molnar
2008-11-12 20:34     ` Maciej Rutecki
2008-11-12 20:40       ` Ingo Molnar

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