From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8151134389F; Sat, 30 May 2026 17:39:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780162746; cv=none; b=uXf79nfOUqgRFu0ykSAtVnCgmQb9P5rYnPgLEs9oWlwoITkOxVCrb8MLvWMkf/NQ4MppdGH/vZSCQpwIW0HCCF/d2NgG/rUA5BISY1hfIVh+lgIQUrSmEZ6KQE+fwh5XCNeB2M7eUje3gKQO8/6UQwENVOCKHIz+0EcdXMhWz9I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780162746; c=relaxed/simple; bh=EHeqSIH1Iw9yb/+UDRZ1wPvsQab2GavGza+ye33fhas=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fUCpClQfDiWgYuQUYRNIyac+USySx7HCu+zs3sHUu5adOkt1RPGxB8VlLfMMSJKHdEHPSt2PiY8xjN/el5dm5y9/+d8I4/Kx5cAGzUmKCZBImYD503/g06puCLwcrnfThfIM0syQ97r5QKiQ4FBzyQFwh94PzCqkDfp9lVKCzMA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=f1ondIM/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="f1ondIM/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A0BED1F00893; Sat, 30 May 2026 17:39:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780162744; bh=xh01yEAob+/Xlb/4jjVzdCe1SHZxHkDbyCGSxv3Gv+E=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=f1ondIM/wjG1zTyzSmOcJfl5i+Fag+iXg8PD1xl1WnLBIcw8UDq61pEMzjtFKWL5S wwm+h/tJc/rswuHlvIGMl/Ui2WQgLFngCXWcNMajVVPJl4kPHZndcwnGOcGsWA9Ggb 1IxMRSpwLu2UA6xato+CdOUsmwIcOomTLWPzBuqY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yifan Wu , Juefei Pu , Yuan Tan , Xin Liu , Haoze Xie , Ao Zhou , Sven Eckelmann , Simon Wunderlich , Sasha Levin Subject: [PATCH 5.15 051/776] batman-adv: hold claim backbone gateways by reference Date: Sat, 30 May 2026 17:56:05 +0200 Message-ID: <20260530160241.629414884@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160240.228940103@linuxfoundation.org> References: <20260530160240.228940103@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Signed-off-by: Sasha Levin --- 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 17687848daec5..fb9aaf82f7136 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); } -- 2.53.0