Subject: [patch 1/3] iucv: wrong irq-disabling locking at module load time

From: Ursula Braun <[email-masked]>
Date: Thu, 07 Feb 2008 15:28:43 +0100

From: Ursula Braun <[email-masked]>

Linux may hang when running af_iucv socket programs concurrently
with a load of module netiucv. iucv_register() tries to take the
iucv_table_lock with spin_lock_irq. This conflicts with
iucv_connect() which has a need for an smp_call_function while
holding the iucv_table_lock.
Solution: use bh-disabling locking in iucv_register()

Signed-off-by: Ursula Braun <[email-masked]>
---

 net/iucv/iucv.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff -urpN linux-2.6/net/iucv/iucv.c linux-2.6-patched/net/iucv/iucv.c
--- linux-2.6/net/iucv/iucv.c	2008-02-07 13:24:12.000000000 +0100
+++ linux-2.6-patched/net/iucv/iucv.c	2008-02-07 13:24:34.000000000 +0100
@@ -693,9 +693,9 @@ int iucv_register(struct iucv_handler *h
 		iucv_setmask_up();
 	INIT_LIST_HEAD(&handler->paths);
 
-	spin_lock_irq(&iucv_table_lock);
+	spin_lock_bh(&iucv_table_lock);
 	list_add_tail(&handler->list, &iucv_handler_list);
-	spin_unlock_irq(&iucv_table_lock);
+	spin_unlock_bh(&iucv_table_lock);
 	rc = 0;
 out_mutex:
 	mutex_unlock(&iucv_register_mutex);

--