Subject: [PATCH 21/22] sfp: fix sfp-bus oops when removing socket/upstream

From: Russell King <[email-masked]>
Date: Tue, 26 Dec 2017 23:15:17 +0000

[ Upstream commit 0b2122e4934c7783d336397864e34ee53aad0965 ]

When we remove a socket or upstream, and the other side isn't
registered, we dereference a NULL pointer, causing a kernel oops.
Fix this.

Fixes: ce0aa27ff3f6 ("sfp: add sfp-bus to bridge between network devices and sfp cages")
Signed-off-by: Russell King <[email-masked]>
Reviewed-by: Florian Fainelli <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 drivers/net/phy/sfp-bus.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/sfp-bus.c b/drivers/net/phy/sfp-bus.c
index 5cb5384697ea..7ae815bee52d 100644
--- a/drivers/net/phy/sfp-bus.c
+++ b/drivers/net/phy/sfp-bus.c
@@ -359,7 +359,8 @@ EXPORT_SYMBOL_GPL(sfp_register_upstream);
 void sfp_unregister_upstream(struct sfp_bus *bus)
 {
 	rtnl_lock();
-	sfp_unregister_bus(bus);
+	if (bus->sfp)
+		sfp_unregister_bus(bus);
 	bus->upstream = NULL;
 	bus->netdev = NULL;
 	rtnl_unlock();
@@ -464,7 +465,8 @@ EXPORT_SYMBOL_GPL(sfp_register_socket);
 void sfp_unregister_socket(struct sfp_bus *bus)
 {
 	rtnl_lock();
-	sfp_unregister_bus(bus);
+	if (bus->netdev)
+		sfp_unregister_bus(bus);
 	bus->sfp_dev = NULL;
 	bus->sfp = NULL;
 	bus->socket_ops = NULL;
-- 
2.14.3