Re: lockdep: BUG: MAX_LOCKDEP_ENTRIES too low!

From: Peter Zijlstra
Date: Thu Dec 19 2013 - 11:01:27 EST


On Thu, Dec 19, 2013 at 10:59:17AM -0500, Dave Jones wrote:
> On Thu, Dec 19, 2013 at 04:51:21PM +0100, Peter Zijlstra wrote:
> > On Thu, Dec 19, 2013 at 10:39:57AM -0500, Sasha Levin wrote:
> > > That discusses lockdep classes, which is actually fine in my case. I ran out of
> > > MAX_LOCKDEP_ENTRIES, which isn't mentioned anywhere in Documentation/ .
> >
> > Yeah, it suffers from the same problem though. Lockdep has static
> > resource allocation and never frees them.
> >
> > The lock classes are the smallest pool and usually run out first, but
> > the same could happen for the entries, after all, the more classes we
> > have the more class connections can happen.
> >
> > Anyway, barring a leak and silly class mistakes like mentioned in the
> > document there's nothing we can do except raise the number.
>
> I tried this. When you bump it to 32k, it fares better but then you
> start seeing "BUG: MAX_LOCKDEP_CHAINS too low!" instead.
> I've not tried bumping that yet, as I've stopped seeing these lately
> due to hitting more serious bugs first.

What are you doing to trigger all this? I don't see these. Are you
loading/unloading modules a lot?
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