Messages in this thread | | | Date | Mon, 30 Oct 2006 19:03:57 +0100 | From | Jens Axboe <> | Subject | Re: 2.6.19-rc3-git7: scsi_device_unbusy: inconsistent lock state |
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On Mon, Oct 30 2006, Ingo Molnar wrote: > > * Jens Axboe <jens.axboe@oracle.com> wrote: > > > > > things may be allocated from that path, so we pass gfp_mask around. I'll > > > > double check it tonight, but I don't currently see what could be wrong. > > > > Would lockdep complain about: > > > > > > > > spin_lock_irqsave(lock, flags); > > > > ... > > > > spin_unlock_irq(lock); > > > > ... > > > > spin_lock_irq(lock); > > > > ... > > > > spin_unlock_irqrestore(lock, flags); > > > > > > this is fine for lockdep IF and only IF there is no "out lock" held > > > around this that requires irqs to be off. So if you do > > > > > > spin_lock_irqsave(lock1, flags); > > > ... > > > spin_lock_irqsave(lock2, flags); > > > spin_unlock_irq(lock2) > > > ... > > > > > > then lockdep WILL complain, and rightfully so, about a violation since > > > lock1 gets violated here ;) > > > > Naturally, that is a bug fair and simple, nothing to do with lockdep. > > well, finding such locking bugs is the main purpose of lockdep, so there > is at least some connection i'd say ;-)
Right, I'm totally with you on that one, I wasn't trying to state otherwise :-)
But we've also had a class of lockdep complaints that simply need some sort of annotation so that lockdep understands there's nothing wrong with it.
-- Jens Axboe
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