6.6-stable review patch. If anyone has any objections, please let me know.
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From: Nikolay Aleksandrov razor@blackwall.org
[ Upstream commit ee87c63f9b2a418f698d79c2991347e31a7d2c27 ]
As Ido pointed out, the static key usage in MST is buggy and should use inc/dec instead of enable/disable because we can have multiple bridges with MST enabled which means a single bridge can disable MST for all. Use static_branch_inc/dec to avoid that. When destroying a bridge decrement the key if MST was enabled.
Fixes: ec7328b59176 ("net: bridge: mst: Multiple Spanning Tree (MST) mode") Reported-by: Ido Schimmel idosch@nvidia.com Closes: https://lore.kernel.org/netdev/20251104120313.1306566-1-razor@blackwall.org/... Signed-off-by: Nikolay Aleksandrov razor@blackwall.org Reviewed-by: Ido Schimmel idosch@nvidia.com Link: https://patch.msgid.link/20251105111919.1499702-3-razor@blackwall.org Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/bridge/br_if.c | 1 + net/bridge/br_mst.c | 10 ++++++++-- net/bridge/br_private.h | 5 +++++ 3 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c index 2450690f98cfa..6ffc81eedf074 100644 --- a/net/bridge/br_if.c +++ b/net/bridge/br_if.c @@ -386,6 +386,7 @@ void br_dev_delete(struct net_device *dev, struct list_head *head) del_nbp(p); }
+ br_mst_uninit(br); br_recalculate_neigh_suppress_enabled(br);
br_fdb_delete_by_port(br, NULL, 0, 1); diff --git a/net/bridge/br_mst.c b/net/bridge/br_mst.c index 3f24b4ee49c27..43a300ae6bfaf 100644 --- a/net/bridge/br_mst.c +++ b/net/bridge/br_mst.c @@ -22,6 +22,12 @@ bool br_mst_enabled(const struct net_device *dev) } EXPORT_SYMBOL_GPL(br_mst_enabled);
+void br_mst_uninit(struct net_bridge *br) +{ + if (br_opt_get(br, BROPT_MST_ENABLED)) + static_branch_dec(&br_mst_used); +} + int br_mst_get_info(const struct net_device *dev, u16 msti, unsigned long *vids) { const struct net_bridge_vlan_group *vg; @@ -225,9 +231,9 @@ int br_mst_set_enabled(struct net_bridge *br, bool on, return err;
if (on) - static_branch_enable(&br_mst_used); + static_branch_inc(&br_mst_used); else - static_branch_disable(&br_mst_used); + static_branch_dec(&br_mst_used);
br_opt_toggle(br, BROPT_MST_ENABLED, on); return 0; diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index 798960ef2dcd0..c8a4e3b39b0e2 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -1899,6 +1899,7 @@ int br_mst_fill_info(struct sk_buff *skb, const struct net_bridge_vlan_group *vg); int br_mst_process(struct net_bridge_port *p, const struct nlattr *mst_attr, struct netlink_ext_ack *extack); +void br_mst_uninit(struct net_bridge *br); #else static inline bool br_mst_is_enabled(const struct net_bridge_port *p) { @@ -1934,6 +1935,10 @@ static inline int br_mst_process(struct net_bridge_port *p, { return -EOPNOTSUPP; } + +static inline void br_mst_uninit(struct net_bridge *br) +{ +} #endif
struct nf_br_ops {