Commit 9ea19481 authored Nov 16, 2010 by John Fastabend Committed by David S. Miller Nov 17, 2010

net: zero kobject in rx_queue_release



netif_set_real_num_rx_queues() can decrement and increment
the number of rx queues. For example ixgbe does this as
features and offloads are toggled. Presumably this could
also happen across down/up on most devices if the available
resources changed (cpu offlined).

The kobject needs to be zero'd in this case so that the
state is not preserved across kobject_put()/kobject_init_and_add().

This resolves the following error report.

ixgbe 0000:03:00.0: eth2: NIC Link is Up 10 Gbps, Flow Control: RX/TX
kobject (ffff880324b83210): tried to init an initialized object, something is seriously wrong.
Pid: 1972, comm: lldpad Not tainted 2.6.37-rc18021qaz+ #169
Call Trace:
 [<ffffffff8121c940>] kobject_init+0x3a/0x83
 [<ffffffff8121cf77>] kobject_init_and_add+0x23/0x57
 [<ffffffff8107b800>] ? mark_lock+0x21/0x267
 [<ffffffff813c6d11>] net_rx_queue_update_kobjects+0x63/0xc6
 [<ffffffff813b5e0e>] netif_set_real_num_rx_queues+0x5f/0x78
 [<ffffffffa0261d49>] ixgbe_set_num_queues+0x1c6/0x1ca [ixgbe]
 [<ffffffffa0262509>] ixgbe_init_interrupt_scheme+0x1e/0x79c [ixgbe]
 [<ffffffffa0274596>] ixgbe_dcbnl_set_state+0x167/0x189 [ixgbe]

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 5811662b

net/core/net-sysfs.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -711,13 +711,18 @@ static void rx_queue_release(struct kobject *kobj)


		map = rcu_dereference_raw(queue->rps_map);
		if (map)
		if (map) {
		RCU_INIT_POINTER(queue->rps_map, NULL);
		call_rcu(&map->rcu, rps_map_release);
		}

		flow_table = rcu_dereference_raw(queue->rps_flow_table);
		if (flow_table)
		if (flow_table) {
		RCU_INIT_POINTER(queue->rps_flow_table, NULL);
		call_rcu(&flow_table->rcu, rps_dev_flow_table_release);
		}

		memset(kobj, 0, sizeof(*kobj));
		dev_put(queue->dev);
		}

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