[PATCH batadv] batman-adv: bla: prevent CRC corruptions after claim flush

When batadv_bla_del_backbone_claims() tried to remove all claims of a
backbone, it sets the CRC to 0. It assumes that the it had the last
reference of the claims because batadv_claim_release() (which runs after
the last reference was released), is XORing the crc16 of the claim address
with the backbone CRC.

If there would be a parallel holder of any of these references, it could
happen that the backbone CRC is (0 ^ crc16(delayed_released_claim)). Which
is the wrong starting point for the new claims it may receive when the
remote answers the claim request from batadv_bla_send_request().

This reinitializations can be completely dropped to avoid this problem.
batadv_claim_release() will take care of fixing the backbone CRC.

Fixes: a9ce0dc43e2c ("batman-adv: add basic bridge loop avoidance code")
Signed-off-by: Sven Eckelmann <[email protected]>
---
 net/batman-adv/bridge_loop_avoidance.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c
index e18e9885..146ead5c 100644
--- a/net/batman-adv/bridge_loop_avoidance.c
+++ b/net/batman-adv/bridge_loop_avoidance.c
@@ -325,11 +325,6 @@ batadv_bla_del_backbone_claims(struct batadv_bla_backbone_gw *backbone_gw)
 		}
 		spin_unlock_bh(list_lock);
 	}
-
-	/* all claims gone, initialize CRC */
-	spin_lock_bh(&backbone_gw->crc_lock);
-	backbone_gw->crc = BATADV_BLA_CRC_INIT;
-	spin_unlock_bh(&backbone_gw->crc_lock);
 }
 
 /**

---
base-commit: e281f6726677f7e8950dad1640d5386867e6d2e6
change-id: 20260705-bla-parallel-crc-corruption-89c627470052

Best regards,
--  
Sven Eckelmann <[email protected]>