wifi: mac80211: account proxy paths against the mesh path limit

Proxy-path churn can drive the interface path counter negative and let
later mesh path additions exceed MESH_MAX_MPATHS.

mesh_path_free_rcu() decrements the interface mpaths counter for entries
from both the mesh and proxy path tables, but mpp_path_add() never
reserves a slot in that counter. Removing or expiring a proxy path
therefore returns a slot that was never charged.

mesh_path_add() uses the same counter to enforce MESH_MAX_MPATHS, so once
it falls below the number of installed paths the limit no longer holds.

Reserve the shared quota before allocating a proxy path and release it on
every unsuccessful addition. Mesh and proxy paths now share one
1024-entry budget, so mpp_path_add() can return -ENOSPC at that limit.

Fixes: ece1a2e7e860 ("mac80211: Remove mesh paths when an interface is removed")
Cc: stable@vger.kernel.org
Assisted-by: LLM sparse kasan
Signed-off-by: Zhao Li <enderaoelyther@gmail.com>
Link: https://patch.msgid.link/20260916113649.28315-3-enderaoelyther@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

0 files changed, 0 insertions, 0 deletions