From: Hans-Joachim Picht <hpicht@redhat.com>
Date: Fri, 16 Nov 2007 13:56:34 +0100
Subject: [s390] qeth: crash during activation of OSA-cards
Message-id: 20071116125634.GO6053@redhat.com
O-Subject: [RHEL5 U2 PATCH 7/14] s390 - qeth: crash during activation of OSA-cards
Bugzilla: 380981

Description
============

If qeth_set_multicast_list() is performed on 2 CPUs in
parallel, card->ip_list may end corrupted.

How the patch addresses this problem:

In function __qeth_delete_all_mc()
remove card->ip_list entry before invoking
qeth_deregister_addr_entry(). Thus a 2nd invocation of
qeth_set_multicast_list() cannot try to remove the
same entry twice.

Bugzilla
=========

BZ 380981
https://bugzilla.redhat.com/show_bug.cgi?id=380981

Upstream status of the patch:
=============================
Patch has been submitted upstream:
http://www.mail-archive.com/netdev@vger.kernel.org/msg49675.html

Test status:
============
Kernel with patch was built and successfully tested

Please ACK.

With best regards,

Hans

diff --git a/drivers/s390/net/qeth_main.c b/drivers/s390/net/qeth_main.c
index 0150f93..51f9fd9 100644
--- a/drivers/s390/net/qeth_main.c
+++ b/drivers/s390/net/qeth_main.c
@@ -803,14 +803,16 @@ __qeth_delete_all_mc(struct qeth_card *card, unsigned long *flags)
 again:
 	list_for_each_entry_safe(addr, tmp, &card->ip_list, entry) {
 		if (addr->is_multicast) {
+			list_del(&addr->entry);
 			spin_unlock_irqrestore(&card->ip_lock, *flags);
 			rc = qeth_deregister_addr_entry(card, addr);
 			spin_lock_irqsave(&card->ip_lock, *flags);
 			if (!rc) {
-				list_del(&addr->entry);
 				kfree(addr);
 				goto again;
 			}
+			else
+				list_add(&addr->entry, &card->ip_list);
 		}
 	}
 }