From: Vladimir Oltean <vladimir.oltean@xxxxxxx>
[ 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@xxxxxxx>
Reviewed-by: Saeed Mahameed <saeed@xxxxxxxxxx>
Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Link: https://lore.kernel.org/r/20221114143551.1906361-1-vladimir.oltean@xxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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);
--
2.35.1
