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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , b.a.t.m.a.n@lists.open-mesh.org, Sven Eckelmann , Sashiko , Simon Wunderlich Subject: [PATCH net-next 13/15] batman-adv: bla: increase hash generation when purging entries Date: Sat, 14 Nov 2026 10:15:54 +0100 Message-ID: <20261114091556.3336038-14-sw@simonwunderlich.de> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261114091556.3336038-1-sw@simonwunderlich.de> References: <20261114091556.3336038-1-sw@simonwunderlich.de> X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Sven Eckelmann If batadv_bla_claim_dump() or batadv_bla_backbone_dump() is preempted during a netlink dump and resumes in the middle of a hash bucket while batadv_bla_del_backbone_claims() or batadv_bla_purge_backbone_gw() concurrently removes an entry, the dump offset will be shifted. Without incrementing the hash generation counter, netlink won't set NLM_F_DUMP_INTR and the userspace will not be informed about the inconsistent dump. Reported-by: Sashiko Closes: https://sashiko.dev/#/bug/linux-83da443f-ce69-4393-a29f-e02b70d1ec96 Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/bridge_loop_avoidance.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c index 9be452f667250..ba410dca1c89c 100644 --- a/net/batman-adv/bridge_loop_avoidance.c +++ b/net/batman-adv/bridge_loop_avoidance.c @@ -319,6 +319,7 @@ batadv_bla_del_backbone_claims(struct batadv_bla_backbone_gw *backbone_gw) continue; hlist_del_rcu(&claim->hash_entry); + atomic_inc(&hash->generation); batadv_claim_put(claim); } spin_unlock_bh(list_lock); @@ -1286,6 +1287,7 @@ static void batadv_bla_purge_backbone_gw(struct batadv_priv *bat_priv, int now) batadv_bla_del_backbone_claims(backbone_gw); hlist_del_rcu(&backbone_gw->hash_entry); + atomic_inc(&hash->generation); break; } spin_unlock_bh(list_lock); -- 2.47.3