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 5BD1D404BF6; Tue, 21 Jul 2026 21:46:58 +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=1784670419; cv=none; b=Ds1uq9ul/A1rGFs/FgLQV1/plH4NyM5v3nhNkeeCbVM5Ve0u6AjPuxbK7mjwZFkRHaDEUvzVkGmO4sOjvL1dOE/KEdxD38gvUGkosJp+Ryx1quG+MWCM810LnHNQQJS1Czh6o8cji5yrE37MNnPnjWLm++dW6hjQ/JCLhaK++x8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784670419; c=relaxed/simple; bh=tGYip14lTJEJKJ06E9chas6caZoW9gFG1byUstbr/os=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=V0/fKcAt4fWcThe6oU8Qv9vC0gTh2UnOi41NSXiSnu0l2jT47m3GfVf6n/bUGw6z8Nd/M+TR+7EfzFRmjHt6hUgTNKSlk3okrCrgRHo6/IqQ15DojopU+v2eJ0YL9Z+lESP2mRvLmNEZ0io4s2odQT328uC69Hv28G51LuotKUI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=gzoQnrvE; 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="gzoQnrvE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C3E51F000E9; Tue, 21 Jul 2026 21:46:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784670417; bh=iHk1E4Lxx9FK0PHVXJ0CUIjjniICR3JZ9Cw41cq7qdI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gzoQnrvEwa83T0vDdjYOfLjqtIHDqLM05/t1VQUAl4x1YxE0cK4fRwrdrcELNEZpe KeKhOXOjX4z9muz2FZn2lyDRfmkRonXyHB/bnAmmHks8Bd68GtMAvi4dKiTPQX1XiD dMHNAsKuCLogR7S66drcZ21cJ9NCG2Oe6Gu1qzYQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jamal Hadi Salim , Paolo Abeni Subject: [PATCH 6.1 0888/1067] net/sched: sch_teql: move rcu_read_lock()/spin_lock() from _bh variants Date: Tue, 21 Jul 2026 17:24:49 +0200 Message-ID: <20260721152444.398045526@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152424.521567757@linuxfoundation.org> References: <20260721152424.521567757@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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jamal Hadi Salim commit 6301f6a34ed86fe6f3b7b3211ea069f3677fc559 upstream. This is a followup based on sashiko comments [1] on commit e5b811fe7931 ("net/sched: sch_teql: Introduce slaves_lock to avoid race condition and UAF") Use plain rcu_read_lock()/spin_lock() in teql_master_xmit() instead of the _bh variants, since ndo_start_xmit is already invoked with BH disabled by the core stack and the _bh primitives can warn in_hardirq() when xmit is reached through netpoll or a softirq xmit path with hard IRQs disabled. Moves rcu_read_lock() after restart: label + adds rcu_read_unlock() before goto restart (fixes the unbounded RCU hold across retries) [1] https://sashiko.dev/#/patchset/20260628111229.669751-1-jhs%40mojatatu.com Signed-off-by: Jamal Hadi Salim Fixes: e5b811fe7931 ("net/sched: sch_teql: Introduce slaves_lock to avoid race condition and UAF") Link: https://patch.msgid.link/20260630150922.238714-1-jhs@mojatatu.com Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman --- net/sched/sch_teql.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) --- a/net/sched/sch_teql.c +++ b/net/sched/sch_teql.c @@ -311,14 +311,14 @@ static netdev_tx_t teql_master_xmit(stru int subq = skb_get_queue_mapping(skb); struct sk_buff *skb_res = NULL; - rcu_read_lock_bh(); - - start = rcu_dereference_bh(master->slaves); - restart: nores = 0; busy = 0; + rcu_read_lock(); + + start = rcu_dereference(master->slaves); + q = start; if (!q) goto drop; @@ -345,17 +345,17 @@ restart: netdev_start_xmit(skb, slave, slave_txq, false) == NETDEV_TX_OK) { __netif_tx_unlock(slave_txq); - spin_lock_bh(&master->slaves_lock); + spin_lock(&master->slaves_lock); if (rcu_dereference_protected(master->slaves, lockdep_is_held(&master->slaves_lock)) == q) rcu_assign_pointer(master->slaves, rcu_dereference_protected(NEXT_SLAVE(q), lockdep_is_held(&master->slaves_lock))); - spin_unlock_bh(&master->slaves_lock); + spin_unlock(&master->slaves_lock); netif_wake_queue(dev); master->tx_packets++; master->tx_bytes += length; - rcu_read_unlock_bh(); + rcu_read_unlock(); return NETDEV_TX_OK; } __netif_tx_unlock(slave_txq); @@ -364,37 +364,38 @@ restart: busy = 1; break; case 1: - spin_lock_bh(&master->slaves_lock); + spin_lock(&master->slaves_lock); if (rcu_dereference_protected(master->slaves, lockdep_is_held(&master->slaves_lock)) == q) rcu_assign_pointer(master->slaves, rcu_dereference_protected(NEXT_SLAVE(q), lockdep_is_held(&master->slaves_lock))); - spin_unlock_bh(&master->slaves_lock); - rcu_read_unlock_bh(); + spin_unlock(&master->slaves_lock); + rcu_read_unlock(); return NETDEV_TX_OK; default: nores = 1; break; } __skb_pull(skb, skb_network_offset(skb)); - } while ((q = rcu_dereference_bh(NEXT_SLAVE(q))) != start); + } while ((q = rcu_dereference(NEXT_SLAVE(q))) != start); if (nores && skb_res == NULL) { skb_res = skb; + rcu_read_unlock(); goto restart; } if (busy) { netif_stop_queue(dev); - rcu_read_unlock_bh(); + rcu_read_unlock(); return NETDEV_TX_BUSY; } master->tx_errors++; drop: master->tx_dropped++; - rcu_read_unlock_bh(); + rcu_read_unlock(); dev_kfree_skb(skb); return NETDEV_TX_OK; }