On Thu, Jun 4, 2026 at 3:50 AM Ido Schimmel [off-list ref] wrote:

On Wed, Jun 03, 2026 at 06:20:38AM +0000, Eric Dumazet wrote:

quoted

@@ -302,9 +304,10 @@ static int br_should_become_designated_port(const struct net_bridge_port *p)
      if (memcmp(&p->designated_root, &br->designated_root, 8))
              return 1;

-     if (br->root_path_cost < p->designated_cost)
+     t = br->root_path_cost - READ_ONCE(p->designated_cost);
+     if (t < 0)
              return 1;
-     else if (br->root_path_cost > p->designated_cost)
+     else if (t > 0)
              return 0;

Eric, I think you meant:

p_designated_cost = READ_ONCE(p->designated_cost);

if (br->root_path_cost < p_designated_cost)
        return 1;
else if (br->root_path_cost > p_designated_cost)
        return 0;

?

quoted

      t = memcmp(&br->bridge_id, &p->designated_bridge, 8);

@@ -344,9 +347,10 @@ static int br_supersedes_port_info(const struct net_bridge_port *p,
      else if (t > 0)
              return 0;

-     if (bpdu->root_path_cost < p->designated_cost)
+     t = bpdu->root_path_cost < READ_ONCE(p->designated_cost);
+     if (t < 0)
              return 1;
-     else if (bpdu->root_path_cost > p->designated_cost)
+     else if (t > 0)
              return 0;

Similarly here?

Oh well, time for a V3 I guess.

Thanks.