When doing "lttng enable-event -k --tracepoint -a":

BUG: sleeping function called from invalid context at kernel/rwsem.c:21
in_atomic(): 0, irqs_disabled(): 0, pid: 7795, name: lttng-sessiond
2 locks held by lttng-sessiond/7795:
 #0:  (sessions_mutex){......}, at: [<ffffffffa0346174>] lttng_session_enable+0x1f/0xa4 [lttng_tracer]
 #1:  (rcu_read_lock){......}, at: [<ffffffffa0330086>] rcu_read_lock+0x0/0x35 [lttng_statedump]
Pid: 7795, comm: lttng-sessiond Tainted: G           O 3.3.8 #1
Call Trace:
 [<ffffffff8106eb8c>] __might_sleep+0x114/0x118
 [<ffffffff8178c220>] down_read+0x26/0x91
 [<ffffffffa03303c1>] lttng_enumerate_task_vm_maps+0x5d/0xe3 [lttng_statedump]
 [<ffffffffa03306fb>] do_lttng_statedump+0xc8/0x2b0 [lttng_statedump]
 [<ffffffff8178b29e>] ? printk+0x68/0x6a
 [<ffffffffa033090a>] lttng_statedump_start+0x27/0x2b [lttng_statedump]
 [<ffffffffa03461d6>] lttng_session_enable+0x81/0xa4 [lttng_tracer]
 [<ffffffffa0346bd8>] lttng_session_ioctl+0x56/0x70 [lttng_tracer]
 [<ffffffff8114d227>] do_vfs_ioctl+0x26a/0x286
 [<ffffffff8113ee60>] ? rcu_read_unlock+0x21/0x23
 [<ffffffff8113efc8>] ? fget_light+0xb6/0xc5
 [<ffffffff8114d299>] sys_ioctl+0x56/0x79
 [<ffffffff81794d10>] tracesys+0xdd/0xe2