From: Ingo Molnar <mingo@elte.hu>
To: Andrew Morton <akpm@osdl.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
linux-kernel <linux-kernel@vger.kernel.org>,
sfr@canb.auug.org.au
Subject: Re: [PATCH] lockdep: annotate i386 apm
Date: Thu, 12 Oct 2006 10:02:12 +0200 [thread overview]
Message-ID: <20061012080212.GA14307@elte.hu> (raw)
In-Reply-To: <20061011233925.c9ba117a.akpm@osdl.org>
* Andrew Morton <akpm@osdl.org> wrote:
> > So, say interrupts were enabled when entering apm_bios_call*(); you now
> > save that in flags, disable interrupts, and enable them again.
> > Upon reaching local_irq_restore(), we'll hit the else branch with irq's
> > enabled and call trace_hardirqs_on(), which goes EEEK!
>
> I'd assumed lockdep was less stupid than that ;) This? Seems a bit
> overdone..
the problem is not lockdep but that the BIOS enables IRQs behind the
back of the kernel. Lockdep needs to be taught about that - if this
happens unconditionally then i'd suggest to insert an unconditional
trace_hardirqs_on() call to after the local_irq_save() that we do prior
calling the BIOS. (that will be a NOP if lockdep is not enabled)
Ingo
next prev parent reply other threads:[~2006-10-12 8:10 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-11 13:40 [PATCH] lockdep: annotate i386 apm Peter Zijlstra
2006-10-11 21:18 ` Andrew Morton
2006-10-12 6:06 ` Peter Zijlstra
2006-10-12 6:39 ` Andrew Morton
2006-10-12 6:50 ` Peter Zijlstra
2006-10-12 7:29 ` Andrew Morton
2006-10-12 8:13 ` Peter Zijlstra
2006-10-12 8:02 ` Ingo Molnar [this message]
2006-10-12 8:26 ` Peter Zijlstra
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