Messages in this thread | | | Date | Sat, 13 Mar 2010 13:58:38 -0800 | From | "Paul E. McKenney" <> | Subject | Re: 2.6.34-rc1: rcu lockdep bug? |
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On Sat, Mar 13, 2010 at 01:33:56PM +0800, Américo Wang wrote: > 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.
Except that it seems to be working correctly for me...
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