Messages in this thread | | | Date | Sat, 13 Mar 2010 13:33:56 +0800 | From | Américo Wang <> | Subject | Re: 2.6.34-rc1: rcu lockdep bug? |
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On Fri, Mar 12, 2010 at 02:37:38PM +0100, Eric Dumazet wrote: >Le vendredi 12 mars 2010 à 21:11 +0800, Américo Wang a écrit : > >> Oh, but lockdep complains about rcu_read_lock(), it said >> rcu_read_lock() can't be used in softirq context. >> >> Am I missing something? > >Well, lockdep might be dumb, I dont know... > >I suggest you read rcu_read_lock_bh kernel doc : > >/** > * rcu_read_lock_bh - mark the beginning of a softirq-only RCU critical >section > * > * This is equivalent of rcu_read_lock(), but to be used when updates > * are being done using call_rcu_bh(). Since call_rcu_bh() callbacks > * consider completion of a softirq handler to be a quiescent state, > * a process in RCU read-side critical section must be protected by > * disabling softirqs. Read-side critical sections in interrupt context > * can use just rcu_read_lock(). > * > */ > > >Last sentence being perfect : > >Read-side critical sections in interrupt context >can use just rcu_read_lock(). >
Yeah, right, then it is more likely to be a bug of rcu lockdep. Paul is looking at it.
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