From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
Dave Hansen <haveblue@us.ibm.com>,
Alexey Dobriyan <adobriyan@sw.ru>
Subject: Re: MAX_LOCKDEP_SUBCLASSES too low in 2.6.23-rc7-mm1
Date: Mon, 24 Sep 2007 12:59:03 -0400 [thread overview]
Message-ID: <20070924165903.GA24220@Krystal> (raw)
In-Reply-To: <20070924183759.085d901c@twins>
* Peter Zijlstra (peterz@infradead.org) wrote:
> On Mon, 24 Sep 2007 12:03:58 -0400 Mathieu Desnoyers
> <mathieu.desnoyers@polymtl.ca> wrote:
>
> > Hi Ingo,
> >
> > I got the following printk when booting 2.6.23-rc7-mm1 :
> >
> > BUG: MAX_LOCKDEP_SUBCLASSES too low!
> > turning off the locking correctness validator.
> >
> > Is it known/correct situation ?
>
> Known, bug in r/o mounts code:
>
> > static void lock_and_coalesce_cpu_mnt_writer_counts(void)
> > {
> > int cpu;
> > struct mnt_writer *cpu_writer;
> >
> > for_each_possible_cpu(cpu) {
> > cpu_writer = &per_cpu(mnt_writers, cpu);
> > spin_lock_nested(&cpu_writer->lock, 42);
> > ^^^^
> >
How could the Ultimate Answer be wrong ? ;)
Cheers,
Mathieu
> > What the heck is going on? Given that MAX_LOCKDEP_SUBCLASSES is only 8,
> > this reliably turns off lockdep at boot.
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
prev parent reply other threads:[~2007-09-24 16:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-24 16:03 MAX_LOCKDEP_SUBCLASSES too low in 2.6.23-rc7-mm1 Mathieu Desnoyers
2007-09-24 16:37 ` Peter Zijlstra
2007-09-24 16:59 ` Mathieu Desnoyers [this message]
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