[PATCH 4.9 55/75] s390/qeth: lock IP table while applying takeover changes

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Julian Wiedmann <jwi@xxxxxxxxxxxxxxxxxx>


[ Upstream commit 8a03a3692b100d84785ee7a834e9215e304c9e00 ]

Modifying the flags of an IP addr object needs to be protected against
eg. concurrent removal of the same object from the IP table.

Fixes: 5f78e29ceebf ("qeth: optimize IP handling in rx_mode callback")
Signed-off-by: Julian Wiedmann <jwi@xxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/s390/net/qeth_l3_sys.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/s390/net/qeth_l3_sys.c
+++ b/drivers/s390/net/qeth_l3_sys.c
@@ -397,6 +397,7 @@ static ssize_t qeth_l3_dev_ipato_enable_
 		goto out;
 	card->ipato.enabled = enable;
 
+	spin_lock_bh(&card->ip_lock);
 	hash_for_each(card->ip_htable, i, addr, hnode) {
 		if (addr->type != QETH_IP_TYPE_NORMAL)
 			continue;
@@ -405,6 +406,7 @@ static ssize_t qeth_l3_dev_ipato_enable_
 		else if (qeth_l3_is_addr_covered_by_ipato(card, addr))
 			addr->set_flags |= QETH_IPA_SETIP_TAKEOVER_FLAG;
 	}
+	spin_unlock_bh(&card->ip_lock);
 out:
 	mutex_unlock(&card->conf_mutex);
 	return rc ? rc : count;