From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dvalin.narfation.org (dvalin.narfation.org [213.160.73.56]) (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 572313A168F for ; Mon, 13 Apr 2026 12:58:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.160.73.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776085081; cv=none; b=eC2VxnRDWLFBec3GGNObqTmmDSJ3cjZO/j1gBmarrLlG89CdqXp+WquKbjPGx7AimNXkHsFQHCfITM45EAOGfzBBFCLGQ6LLjyyqr0U2gf7nZ6TNrqt4BEKF28Xz7zB2Nbq1sFYXDtITzjk7gdIek0rC7EBGo1yQ6m+A3TiJ47g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776085081; c=relaxed/simple; bh=0hhU8bF/g7+KuorLbfuQEfcSITtpxpmRVx2VTBg54VE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=F1zbR5Q5/98TXyNHE8vSSRn3MGon5gI3rUQbPPDWnxB39hRaICXU0RXXUT3vrV5yllpFNTcu9KFv4bsl1EnRvMjAqr4o/qGIIEjVcF2T/hrv9MDnCW5CbMOPbju0u5LDCJTh8ZhKPd/TcVsQ5qLZlGaBuQrC+YhXqyd36yHFpw8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=narfation.org; spf=pass smtp.mailfrom=narfation.org; dkim=pass (1024-bit key) header.d=narfation.org header.i=@narfation.org header.b=qgFa2oPX; arc=none smtp.client-ip=213.160.73.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=narfation.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=narfation.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=narfation.org header.i=@narfation.org header.b="qgFa2oPX" Received: by dvalin.narfation.org (Postfix) id 106E51FF65; Mon, 13 Apr 2026 12:57:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=narfation.org; s=20121; t=1776085078; 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=hWDwxrhvg0AqrCaAKc/qFVuXld1/M0eeFRugf7FkTZA=; b=qgFa2oPXOsjxy2h05p1Ij3F/9kXclLsf3slBVmcl+E2HQI1Bu453vPPGEkdQkW2U+Od6s7 WTgWa9Rcbt5YiBNCwPzvXpJEwi+9cJjQu7HV5qocNlemXnGunRl9/ziByt7/J+9Ujdaor5 fDlwWKohKIZur1vVTzdwbpqXa74vSjY= From: Sven Eckelmann To: stable@vger.kernel.org Cc: Haoze Xie , Yifan Wu , Juefei Pu , Yuan Tan , Xin Liu , Ao Zhou , Sven Eckelmann , Simon Wunderlich Subject: [PATCH 5.10.y] batman-adv: hold claim backbone gateways by reference Date: Mon, 13 Apr 2026 14:57:46 +0200 Message-ID: <20260413125747.124428-1-sven@narfation.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <2026041331-bloomers-stubborn-73ac@gregkh> References: <2026041331-bloomers-stubborn-73ac@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Haoze Xie commit 82d8701b2c930d0e96b0dbc9115a218d791cb0d2 upstream. 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: Sven Eckelmann --- 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 986f707e7d973..ffbd8fa7acce1 100644 --- a/net/batman-adv/bridge_loop_avoidance.c +++ b/net/batman-adv/bridge_loop_avoidance.c @@ -2206,6 +2206,7 @@ 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; @@ -2221,32 +2222,35 @@ 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); - spin_lock_bh(&claim->backbone_gw->crc_lock); - backbone_crc = claim->backbone_gw->crc; - spin_unlock_bh(&claim->backbone_gw->crc_lock); + is_own = batadv_compare_eth(backbone_gw->orig, primary_addr); + + 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; } @@ -2612,6 +2616,7 @@ 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; @@ -2634,9 +2639,13 @@ 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