Messages in this thread | | | Date | Wed, 31 Mar 2010 15:17:55 -0600 | From | Matthew Wilcox <> | Subject | Re: start_kernel(): bug: interrupts were enabled early |
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On Wed, Mar 31, 2010 at 02:05:00PM -0700, H. Peter Anvin wrote: > What I note is that lib/rwsem-spinlock.c seems to be rather inconsistent > in its use of spin_lock_irqsave/spin_lock_irqrestore versus > spin_lock_irq/spin_unlock_irq... in fact, __down_read is the *only* > place where we use the latter as opposed to the former. > > Is that a bug? If so, it would certainly explain this behavior.
It's based on down_read() and down_write() not being callable from interrupt context, or with interrupts disabled (since they can sleep). up_read(), up_write(), down_read_trylock(), down_write_trylock(), downgrade_write() can all be called from interrupt context since they cannot sleep.
-- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."
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