From 89f3502ff6878798be96461b2eebd64ba3c3874c Mon Sep 17 00:00:00 2001 From: Sven Eckelmann Date: Sun, 5 Jul 2026 22:21:50 +0200 Subject: [PATCH] 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. Cc: stable@vger.kernel.org Fixes: 23721387c409 ("batman-adv: add basic bridge loop avoidance code") Signed-off-by: Sven Eckelmann --- 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 a3530cc90c95..3194ccdbce60 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); } /**