Messages in this thread | | | Date | Fri, 29 Aug 2008 01:14:23 -0700 | From | Andrew Morton <> | Subject | Re: 2.6.27-rc4: lots of 'in_atomic():1, irqs_disabled():0' with software-raid1 |
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On Fri, 29 Aug 2008 17:36:08 +1000 Neil Brown <neilb@suse.de> wrote:
> On Thursday August 28, akpm@linux-foundation.org wrote: > > > > I'm curious about how this happened. > > > > afaict from reading the code, this: > > > > rcu_read_lock(); > > might_sleep(); > > rcu_read_unlock(); > > > > will warn if CONFIG_PREEMPT_RCU=n but won't warn if > > CONFIG_PREEMPT_RCU=y. If correct, that's a nasty trap. > > > > Is that what you did? > > Uhm.. > $ grep PREEMPT /home/src/md-x86-64/.config > CONFIG_PREEMPT_NONE=y > # CONFIG_PREEMPT_VOLUNTARY is not set > # CONFIG_PREEMPT is not set > $ grep DEBUG_SPIN /home/src/md-x86-64/.config > CONFIG_DEBUG_SPINLOCK=y > CONFIG_DEBUG_SPINLOCK_SLEEP=y > $ grep RCU /home/src/md-x86-64/.config > CONFIG_CLASSIC_RCU=y > # CONFIG_RCU_TORTURE_TEST is not set > > This definitely doesn't report an error if I put "might_sleep" inside > rcu_read_lock. I tried to figure out why but got lost.
CONFIG_DEBUG_SPINLOCK_SLEEP doesn't do much useful without CONFIG_PREEMPT=y. Perhaps we could improve the Kconfig situation there.
The most fine Documentation/SubmitChecklist instructeth:
12: Has been tested with CONFIG_PREEMPT, CONFIG_DEBUG_PREEMPT, CONFIG_DEBUG_SLAB, CONFIG_DEBUG_PAGEALLOC, CONFIG_DEBUG_MUTEXES, CONFIG_DEBUG_SPINLOCK, CONFIG_DEBUG_SPINLOCK_SLEEP all simultaneously enabled.
(which might need updating for new goodies - it was written a while ago).
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