From patchwork Fri Feb 7 09:58:20 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Simon Wunderlich X-Patchwork-Id: 13964720 X-Patchwork-Delegate: kuba@kernel.org 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 B327B1DE2C5; Fri, 7 Feb 2025 10:05:11 +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=1738922713; cv=none; b=a/iSsPcBlA8C2XrHLSR4jByeIg0pajHo/eaIk1APQTCWw3IwBtZ8+JPnmm+mudKuSOfdWuseakBz9l2WXks4EgzU4SDSpCS4q5y+41wyNG5n0E/EPkJnBjZJyz4S8AZpzLW+jkgZhA/bS0YFvbAL0BNQ9aBxe/PMw6Z40hpkYdg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738922713; c=relaxed/simple; bh=7v3TujD06KFAViD9d3T0ENPYjJimOlUrSpxn1dfBAXs=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=O4r2uwqVYUgq0G/mvkav9prjzD2eK8TqPewfyf5REtizGR2XkVup8z385LCIImbF4hftl0irzlyW5n9tokGpoM/iTLBB4mSF4ylYY+LTiHlEvFaHE7gsQS8PdnrV8BtCNHGyqvb4Cq19BnXxi52M7ZI4svNSYlL7BM8RNIlc9U8= 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; 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 Received: from kero.packetmixer.de (p200300c59725eFd8C202009B11B64500.dip0.t-ipconnect.de [IPv6:2003:c5:9725:efd8:c202:9b:11b6:4500]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.simonwunderlich.de (Postfix) with ESMTPSA id B0AA7FA14B; Fri, 7 Feb 2025 10:58:29 +0100 (CET) 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, Andy Strohman , stable@vger.kernel.org, Sven Eckelmann , Simon Wunderlich Subject: [PATCH 1/4] batman-adv: fix panic during interface removal Date: Fri, 7 Feb 2025 10:58:20 +0100 Message-Id: <20250207095823.26043-2-sw@simonwunderlich.de> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250207095823.26043-1-sw@simonwunderlich.de> References: <20250207095823.26043-1-sw@simonwunderlich.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org From: Andy Strohman Reference counting is used to ensure that batadv_hardif_neigh_node and batadv_hard_iface are not freed before/during batadv_v_elp_throughput_metric_update work is finished. But there isn't a guarantee that the hard if will remain associated with a soft interface up until the work is finished. This fixes a crash triggered by reboot that looks like this: Call trace: batadv_v_mesh_free+0xd0/0x4dc [batman_adv] batadv_v_elp_throughput_metric_update+0x1c/0xa4 process_one_work+0x178/0x398 worker_thread+0x2e8/0x4d0 kthread+0xd8/0xdc ret_from_fork+0x10/0x20 (the batadv_v_mesh_free call is misleading, and does not actually happen) I was able to make the issue happen more reliably by changing hardif_neigh->bat_v.metric_work work to be delayed work. This allowed me to track down and confirm the fix. Cc: stable@vger.kernel.org Fixes: c833484e5f38 ("batman-adv: ELP - compute the metric based on the estimated throughput") Signed-off-by: Andy Strohman [sven@narfation.org: prevent entering batadv_v_elp_get_throughput without soft_iface] Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/bat_v_elp.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/net/batman-adv/bat_v_elp.c b/net/batman-adv/bat_v_elp.c index 1d704574e6bf..fbf499bcc671 100644 --- a/net/batman-adv/bat_v_elp.c +++ b/net/batman-adv/bat_v_elp.c @@ -66,12 +66,19 @@ static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface) static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh) { struct batadv_hard_iface *hard_iface = neigh->if_incoming; + struct net_device *soft_iface = hard_iface->soft_iface; struct ethtool_link_ksettings link_settings; struct net_device *real_netdev; struct station_info sinfo; u32 throughput; int ret; + /* don't query throughput when no longer associated with any + * batman-adv interface + */ + if (!soft_iface) + return BATADV_THROUGHPUT_DEFAULT_VALUE; + /* if the user specified a customised value for this interface, then * return it directly */ @@ -141,7 +148,7 @@ static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh) default_throughput: if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) { - batadv_info(hard_iface->soft_iface, + batadv_info(soft_iface, "WiFi driver or ethtool info does not provide information about link speeds on interface %s, therefore defaulting to hardcoded throughput values of %u.%1u Mbps. Consider overriding the throughput manually or checking your driver.\n", hard_iface->net_dev->name, BATADV_THROUGHPUT_DEFAULT_VALUE / 10,