From: Vladimir Oltean vladimir.oltean@nxp.com
[ Upstream commit 4e0c19fcb8b5323716140fa82b79aa9f60e60407 ]
In the initial commit dc452a471dba ("net: dsa: introduce tagger-owned storage for private and shared data"), we had a call to tag_ops->disconnect(dst) issued from dsa_tree_free(), which is called at tree teardown time.
There were problems with connecting to a switch tree as a whole, so this got reworked to connecting to individual switches within the tree. In this process, tag_ops->disconnect(ds) was made to be called only from switch.c (cross-chip notifiers emitted as a result of dynamic tag proto changes), but the normal driver teardown code path wasn't replaced with anything.
Solve this problem by adding a function that does the opposite of dsa_switch_setup_tag_protocol(), which is called from the equivalent spot in dsa_switch_teardown(). The positioning here also ensures that we won't have any use-after-free in tagging protocol (*rcv) ops, since the teardown sequence is as follows:
dsa_tree_teardown -> dsa_tree_teardown_master -> dsa_master_teardown -> unsets master->dsa_ptr, making no further packets match the ETH_P_XDSA packet type handler -> dsa_tree_teardown_ports -> dsa_port_teardown -> dsa_slave_destroy -> unregisters DSA net devices, there is even a synchronize_net() in unregister_netdevice_many() -> dsa_tree_teardown_switches -> dsa_switch_teardown -> dsa_switch_teardown_tag_protocol -> finally frees the tagger-owned storage
Fixes: 7f2973149c22 ("net: dsa: make tagging protocols connect to individual switches from a tree") Signed-off-by: Vladimir Oltean vladimir.oltean@nxp.com Reviewed-by: Saeed Mahameed saeed@kernel.org Reviewed-by: Florian Fainelli f.fainelli@gmail.com Link: https://lore.kernel.org/r/20221114143551.1906361-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/dsa/dsa2.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c index e537655e442b..befa954b0a47 100644 --- a/net/dsa/dsa2.c +++ b/net/dsa/dsa2.c @@ -850,6 +850,14 @@ static int dsa_switch_setup_tag_protocol(struct dsa_switch *ds) return err; }
+static void dsa_switch_teardown_tag_protocol(struct dsa_switch *ds) +{ + const struct dsa_device_ops *tag_ops = ds->dst->tag_ops; + + if (tag_ops->disconnect) + tag_ops->disconnect(ds); +} + static int dsa_switch_setup(struct dsa_switch *ds) { struct dsa_devlink_priv *dl_priv; @@ -953,6 +961,8 @@ static void dsa_switch_teardown(struct dsa_switch *ds) ds->slave_mii_bus = NULL; }
+ dsa_switch_teardown_tag_protocol(ds); + if (ds->ops->teardown) ds->ops->teardown(ds);