From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.simonwunderlich.de (mail.simonwunderlich.de [23.88.38.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D50ED2E8B8A; Wed, 8 Apr 2026 11:03:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=23.88.38.48 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775646200; cv=none; b=ge1OKy/mVSw+gl9gP2iPY6c4Pe8nU8/6dW2j+v6yj9sT6gNsRz9PpGVKaX7FGAwlMnZvSWNCK7W9mXVKX6F7RlZ+oi+5GbZZ2wZg4QeRMD+Fcimvtx2/Rd+pGBXspTduD8aaF2gM/oLlZv2vyz89Ff75QKOffbbdV3iA0/krJEk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775646200; c=relaxed/simple; bh=08Q1dMV/7+KzD4lHA2fx/meL9kTyGNMncxHMHrZ4U7o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bdylxe6UWxhG5XJw0z9JhLGsI7klwIycHdJYo9ccFx6numWLzXVP8i/MG5ul5LpQan91EbiWKb4hs0jH23JPV6FZ6gTUUnLiT1YJoE/QVB7BhJgDMd2cJ61zQTlYBHdvwL/fs7kGYE1cSKR0leBfhr6fu4qdKPUiX/UZ/9/bqoM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=simonwunderlich.de; spf=pass smtp.mailfrom=simonwunderlich.de; dkim=pass (2048-bit key) header.d=simonwunderlich.de header.i=@simonwunderlich.de header.b=Dyy+MT5O; arc=none smtp.client-ip=23.88.38.48 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=simonwunderlich.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=simonwunderlich.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=simonwunderlich.de header.i=@simonwunderlich.de header.b="Dyy+MT5O" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=simonwunderlich.de; s=09092022; t=1775646195; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=yp6I7b0bf/KYoASlU+siFF3CuLzV71ZDF6eOe3F2lZ0=; b=Dyy+MT5O8I06JJDfM9g8RSY3afbY86g6g1TSm9gQMXsApj5EdkcpxRFpUSqXKclZDKJeU1 AK7O1Lx2BdJx3AntN2RMFtWCply21IeRCH4mQySBn5ouTtrt0VFK8IyeQNygnnujH5IejI jAfpqsNB3GfcW9GVXn2B3/16OVi6W6PKF3pR8Jz6v3w89zJlNZYSXOyLW/u7ptmjAafqJp PLCFjs6KOiH9zidQ/wcXxkiuSEjiWoMeK8fke4Ube2y24RrTVazmvAsZ9mq7KfLXrXr19f G34Epqe/2UMDzd9T/x8I/S+H46k6eByth7sIVj4b3vV1UbeVJaV8cDBvRAyegA== From: Simon Wunderlich To: davem@davemloft.net, kuba@kernel.org Cc: netdev@vger.kernel.org, b.a.t.m.a.n@lists.open-mesh.org, Haoze Xie , stable@vger.kernel.org, Yifan Wu , Juefei Pu , Yuan Tan , Xin Liu , Ao Zhou , Sven Eckelmann , Simon Wunderlich Subject: [PATCH net 2/2] batman-adv: hold claim backbone gateways by reference Date: Wed, 8 Apr 2026 13:02:55 +0200 Message-ID: <20260408110255.976389-3-sw@simonwunderlich.de> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260408110255.976389-1-sw@simonwunderlich.de> References: <20260408110255.976389-1-sw@simonwunderlich.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Haoze Xie batadv_bla_add_claim() can replace claim->backbone_gw and drop the old gateway's last reference while readers still follow the pointer. The netlink claim dump path dereferences claim->backbone_gw->orig and takes claim->backbone_gw->crc_lock without pinning the underlying backbone gateway. batadv_bla_check_claim() still has the same naked pointer access pattern. Reuse batadv_bla_claim_get_backbone_gw() in both readers so they operate on a stable gateway reference until the read-side work is complete. This keeps the dump and claim-check paths aligned with the lifetime rules introduced for the other BLA claim readers. Fixes: 23721387c409 ("batman-adv: add basic bridge loop avoidance code") Fixes: 04f3f5bf1883 ("batman-adv: add B.A.T.M.A.N. Dump BLA claims via netlink") Cc: stable@vger.kernel.org Reported-by: Yifan Wu Reported-by: Juefei Pu Co-developed-by: Yuan Tan Signed-off-by: Yuan Tan Suggested-by: Xin Liu Signed-off-by: Haoze Xie Signed-off-by: Ao Zhou Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/bridge_loop_avoidance.c | 27 +++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c index 3dc791c15bf72..648fa97ea913f 100644 --- a/net/batman-adv/bridge_loop_avoidance.c +++ b/net/batman-adv/bridge_loop_avoidance.c @@ -2130,6 +2130,7 @@ batadv_bla_claim_dump_entry(struct sk_buff *msg, u32 portid, struct batadv_bla_claim *claim) { const u8 *primary_addr = primary_if->net_dev->dev_addr; + struct batadv_bla_backbone_gw *backbone_gw; u16 backbone_crc; bool is_own; void *hdr; @@ -2145,32 +2146,35 @@ batadv_bla_claim_dump_entry(struct sk_buff *msg, u32 portid, genl_dump_check_consistent(cb, hdr); - is_own = batadv_compare_eth(claim->backbone_gw->orig, - primary_addr); + backbone_gw = batadv_bla_claim_get_backbone_gw(claim); + + is_own = batadv_compare_eth(backbone_gw->orig, primary_addr); - spin_lock_bh(&claim->backbone_gw->crc_lock); - backbone_crc = claim->backbone_gw->crc; - spin_unlock_bh(&claim->backbone_gw->crc_lock); + spin_lock_bh(&backbone_gw->crc_lock); + backbone_crc = backbone_gw->crc; + spin_unlock_bh(&backbone_gw->crc_lock); if (is_own) if (nla_put_flag(msg, BATADV_ATTR_BLA_OWN)) { genlmsg_cancel(msg, hdr); - goto out; + goto put_backbone_gw; } if (nla_put(msg, BATADV_ATTR_BLA_ADDRESS, ETH_ALEN, claim->addr) || nla_put_u16(msg, BATADV_ATTR_BLA_VID, claim->vid) || nla_put(msg, BATADV_ATTR_BLA_BACKBONE, ETH_ALEN, - claim->backbone_gw->orig) || + backbone_gw->orig) || nla_put_u16(msg, BATADV_ATTR_BLA_CRC, backbone_crc)) { genlmsg_cancel(msg, hdr); - goto out; + goto put_backbone_gw; } genlmsg_end(msg, hdr); ret = 0; +put_backbone_gw: + batadv_backbone_gw_put(backbone_gw); out: return ret; } @@ -2448,6 +2452,7 @@ int batadv_bla_backbone_dump(struct sk_buff *msg, struct netlink_callback *cb) bool batadv_bla_check_claim(struct batadv_priv *bat_priv, u8 *addr, unsigned short vid) { + struct batadv_bla_backbone_gw *backbone_gw; struct batadv_bla_claim search_claim; struct batadv_bla_claim *claim = NULL; struct batadv_hard_iface *primary_if = NULL; @@ -2470,9 +2475,13 @@ bool batadv_bla_check_claim(struct batadv_priv *bat_priv, * return false. */ if (claim) { - if (!batadv_compare_eth(claim->backbone_gw->orig, + backbone_gw = batadv_bla_claim_get_backbone_gw(claim); + + if (!batadv_compare_eth(backbone_gw->orig, primary_if->net_dev->dev_addr)) ret = false; + + batadv_backbone_gw_put(backbone_gw); batadv_claim_put(claim); } -- 2.47.3