Subject: [PATCH] ehea: Fix memory hotplug oops

From: Anton Blanchard <[email-masked]>
Date: Wed, 11 May 2011 12:17:10 +1000

The ehea driver oopses during memory hotplug if the ports are not
up. A simple testcase:

# ifconfig ethX down
# echo offline > /sys/devices/system/memory/memory32/state

Oops: Kernel access of bad area, sig: 11 [#1]
last sysfs file: /sys/devices/system/memory/memory32/state
REGS: c000000709393110 TRAP: 0300   Not tainted  (2.6.39-rc2-01385-g7ef73bc-dirty)
DAR: 0000000000000000, DSISR: 40000000
...
NIP [c000000000067c98] .__wake_up_common+0x48/0xf0
LR [c00000000006d034] .__wake_up+0x54/0x90
Call Trace:
[c00000000006d034] .__wake_up+0x54/0x90
[d000000006bb6270] .ehea_rereg_mrs+0x140/0x730 [ehea]
[d000000006bb69c4] .ehea_mem_notifier+0x164/0x170 [ehea]
[c0000000006fc8a8] .notifier_call_chain+0x78/0xf0
[c0000000000b3d70] .__blocking_notifier_call_chain+0x70/0xb0
[c000000000458d78] .memory_notify+0x28/0x40
[c0000000001871d8] .remove_memory+0x208/0x6d0
[c000000000458264] .memory_section_action+0x94/0x140
[c0000000004583ec] .memory_block_change_state+0xdc/0x1d0
[c0000000004585cc] .store_mem_state+0xec/0x160
[c00000000044768c] .sysdev_store+0x3c/0x50
[c00000000020b48c] .sysfs_write_file+0xec/0x1f0
[c00000000018f86c] .vfs_write+0xec/0x1e0
[c00000000018fa88] .SyS_write+0x58/0xd0

To fix this, initialise the waitqueues during port probe instead
of port open.

Signed-off-by: Anton Blanchard <[email-masked]>
Cc: [email-masked]
---

Index: linux-net/drivers/net/ehea/ehea_main.c
===================================================================
--- linux-net.orig/drivers/net/ehea/ehea_main.c	2011-05-11 11:54:18.751672569 +1000
+++ linux-net/drivers/net/ehea/ehea_main.c	2011-05-11 11:56:27.423964456 +1000
@@ -2688,9 +2688,6 @@ static int ehea_open(struct net_device *
 		netif_start_queue(dev);
 	}
 
-	init_waitqueue_head(&port->swqe_avail_wq);
-	init_waitqueue_head(&port->restart_wq);
-
 	mutex_unlock(&port->port_lock);
 
 	return ret;
@@ -3278,6 +3275,9 @@ struct ehea_port *ehea_setup_single_port
 
 	INIT_WORK(&port->reset_task, ehea_reset_port);
 
+	init_waitqueue_head(&port->swqe_avail_wq);
+	init_waitqueue_head(&port->restart_wq);
+
 	ret = register_netdev(dev);
 	if (ret) {
 		pr_err("register_netdev failed. ret=%d\n", ret);