Re: sctp: hang in sctp_remaddr_seq_show

[Vlad Yasevich]

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();

-vlad
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