From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.4]) (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 0EA9E39FCA5; Thu, 30 Apr 2026 07:18:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.4 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777533500; cv=none; b=uWBCN6aQkCYkPJ431viEsedWI98fxzBzp+wo1m6wx5pers6mtqdVKC5Vz6wAAS1niaZoplkmf4/oIMf8toJeI98bSayWuLMmN+YXuw3Z6Xq7GtQXRjQEwtiTcK/2k+Oz/7lhT+d9S2S4RA+4YTxlcMbqlNzhOB4KjGqQaqwK0QU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777533500; c=relaxed/simple; bh=Q7foYfp8ARoIBQqg1d2+D9rs0xQ21+cNmUKlyxxvTFE=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=I1lt+zsczI3HvXIHEjrDMij8ONKcFOR5anwf5jl2UBrzVRDxPpb550pko9mpgsIoqV+HOuCeAxDEoYsaFcNlL6FClu6sXdmsqOU8OzBju8rK7HIUwUFPUo5YHk3H7hZ+pFtxRDRNdICBBq6vpSktOBm0cKnfw3EEIqSVMBU7PS8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=bhfNzI/w; arc=none smtp.client-ip=220.197.31.4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="bhfNzI/w" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=ek Cy/GX+5k72OAkBDR9bmLdXrX1HQq/QVHZD/S3Dr/A=; b=bhfNzI/wZX/r+rr2g9 yF4Im+Qn4RJ5dYPadk8tB2CeBvw6vzCYOdVaUsHhinRYH4rgwkliidJQcVVkSADF 3uZaKO/n3T9h44YgnllO7IEoone5uVvI4SeJyLEMzRtGt9BS4LibpXdiZEe6dry3 juSS9f4gL9JOW2wtvHTMU6Fqw= Received: from pek-lpg-core5.wrs.com (unknown []) by gzga-smtp-mtada-g0-3 (Coremail) with SMTP id _____wAX4WzdAfNpXUOSCg--.61089S2; Thu, 30 Apr 2026 15:16:46 +0800 (CST) From: Robert Garcia To: stable@vger.kernel.org, Haoze Xie Cc: Simon Wunderlich , Robert Garcia , Yifan Wu , Juefei Pu , Yuan Tan , Xin Liu , Ao Zhou , Sven Eckelmann , Marek Lindner , Antonio Quartulli , "David S . Miller" , Jakub Kicinski , Andrew Lunn , b.a.t.m.a.n@lists.open-mesh.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 5.15.y] batman-adv: hold claim backbone gateways by reference Date: Thu, 30 Apr 2026 15:16:45 +0800 Message-Id: <20260430071645.3030702-1-rob_garcia@163.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:_____wAX4WzdAfNpXUOSCg--.61089S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxXryxGFykCrWrWr13GF1ftFb_yoWrCr15pF 17Kw1rKrs7Xws7X342yry2gF1UXrs3GrW7WryUGF1Iyw1jyr18K345KF1IvF4YyFyqkrs8 Zr1Ykr17urs8CrUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zR4SoJUUUUU= X-CM-SenderInfo: 5uresw5dufxti6rwjhhfrp/xtbC5h7OOmnzAd4ToQAA37 From: Haoze Xie [ Upstream commit 82d8701b2c930d0e96b0dbc9115a218d791cb0d2 ] 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 Signed-off-by: Robert Garcia --- 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 17687848daec..fb9aaf82f713 100644 --- a/net/batman-adv/bridge_loop_avoidance.c +++ b/net/batman-adv/bridge_loop_avoidance.c @@ -2131,6 +2131,7 @@ batadv_bla_claim_dump_entry(struct sk_buff *msg, u32 portid, struct batadv_bla_claim *claim) { u8 *primary_addr = primary_if->net_dev->dev_addr; + struct batadv_bla_backbone_gw *backbone_gw; u16 backbone_crc; bool is_own; void *hdr; @@ -2146,32 +2147,35 @@ 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; } @@ -2467,6 +2471,7 @@ 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; @@ -2489,9 +2494,13 @@ 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); } -- 2.34.1