Messages in this thread | | | Date | Wed, 14 Jan 2009 03:00:40 +0100 | From | Nick Piggin <> | Subject | Re: next-20090107: WARNING: at kernel/sched.c:4435 sub_preempt_count |
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On Sun, Jan 11, 2009 at 03:49:45AM +0100, Ingo Molnar wrote: > > * Alexey Zaytsev <alexey.zaytsev@gmail.com> wrote: > > > One more instance of http://marc.info/?l=linux-kernel&m=123134586202636&w=2 > > Added Ingo Molnar to CC. > > added Nick on Cc:. Nick, it's about: > > > commit 7317d7b87edb41a9135e30be1ec3f7ef817c53dd > > Author: Nick Piggin <nickpiggin@yahoo.com.au> > > Date: Tue Sep 30 20:50:27 2008 +1000 > > > > sched: improve preempt debugging > > causing a seemingly spurious warning.
I don't know how it is spurious... Presumably the sequence _would_ have caused preempt count to go negative if the bkl were not held...
__do_softirq does a __local_bh_disable on entry, and it seems like the _local_bh_enable on exit is what causes this warning. So something is unbalanced somehow. Or is it some weird thing we do in early boot that I am missing?
Can you put in some printks around these functions in early boot to get an idea of what preempt_count is doing?
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