On Mon, Mar 18, 2013 at 11:31:06AM -0400, Vlad Yasevich wrote:On 03/18/2013 11:25 AM, Eric Dumazet wrote:Vlads, right. We need to grab the rcu lock before the read lock, but we shouldOn 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();
probably use the rcu_read_lock_bh variant, since we're going to disable bottom
halves anyway.
Neil
-vlad
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