Re: bug in tty ldisc and friends

From: Ingo Molnar
Date: Tue Jun 16 2009 - 06:29:36 EST

* Ingo Molnar <mingo@xxxxxxx> wrote:

> * Ingo Molnar <mingo@xxxxxxx> wrote:
> > > On bootup with a totally generic Fedora 11, thinkpad setup
> > > with the kernel swapped for current git head. Will send the
> > > .config off list and build it with a 1M entry stack trace
> > > again.
> >
> > Nah, dont waste your time on that for now - if it's reproducible
> > on simple bootup then i will be able to trigger it once i have
> > your config.
> update: i do trigger it too with your config:

I have a potential workaround, please disable:


does it get you below the limit? Here it gives:

lock-classes: 549 [max: 8191]
direct dependencies: 3288 [max: 16384]
indirect dependencies: 6753
all direct dependencies: 49282
dependency chains: 3384 [max: 32768]
dependency chain hlocks: 9901 [max: 163840]
in-hardirq chains: 21
in-softirq chains: 243
in-process chains: 3120
stack-trace entries: 81205 [max: 262144]
combined max dependencies: 16753528

We are now well below the limit for stack-trace entries.

This is something we noticed recently: dma-debug uses a lot of lock
classes and thus creates a really large lock-graph, depleting the
reserves quickly.

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