On Mon, Mar 18, 2013 at 11:31:06AM -0400, Vlad Yasevich wrote: > On 03/18/2013 11:25 AM, Eric Dumazet wrote: > >On Mon, 2013-03-18 at 07:04 -0400, Neil Horman wrote: > > > >>I'm not sure why the process would never get back to the schedule, but looking > >>at the sctp_remaddr_seq_show function, I think that we should convert this > >>sequence: > >> sctp_local_bh_disable(); > >> read_lock(&head->lock); > >> rcu_read_lock(); > >> > >>to this: > >> read_lock(&head->lock); > >> rcu_read_lock_bh(); > >> > >>Neil > > > >I dont think so. > > > >BH needs to be disabled before read_lock(&head->lock); > > > >or else, write_lock() could deadlock (assuming it can be called from BH) > > > > > > If anything, this should probably be done like this: > > rcu_read_lock(); > read_lock_bh(&head->lock) > ... > > read_unlock_bh(&head->lock) > rcu_read_unlock(); > Vlads, right. We need to grab the rcu lock before the read lock, but we should probably use the rcu_read_lock_bh variant, since we're going to disable bottom halves anyway. Neil > -vlad > -- > To unsubscribe from this list: send the line "unsubscribe linux-sctp" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
