From patchwork Mon Nov 21 17:46:01 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 13051485 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8EE9AC4332F for ; Mon, 21 Nov 2022 17:46:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229760AbiKURqP (ORCPT ); Mon, 21 Nov 2022 12:46:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37508 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230115AbiKURqN (ORCPT ); Mon, 21 Nov 2022 12:46:13 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0B5648753 for ; Mon, 21 Nov 2022 09:46:12 -0800 (PST) From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1669052771; 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=x7EazyHGHCpeTiiHucwroXGYdDx6pSWXMjFRJN0efiU=; b=g8rxkBgEmxG1B22zKzCcwsiH78DNtwC1uds3QRaiv+kJnzKZA/1TPPO4Rh7BkFZbdDTGCT CbCvQqM7O3mkL4p/yNEr8zd8CgAJ7l23/YIR4kHwgvX5QJZ+BHscU8ox/8HH1Qj8OHlZLW xeNwlZS1UaPlVtDNjOPwryAJcVSl8vtue3NGYHEma4pd2yYjChE3RJLWTpvXz/xHR4in+i Hx8mjgkyVS83a63KcseypVnfHHYrnQoWN0u6L+aElhMd1g7BwffVv/lp+eT6rVIppnUxVm vUXsxhExyCvq/Uc4qPXYRdNDqUoxPEmvCTr5/Svsp64Wr5eH9qBSFC3OXb6jZA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1669052771; 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=x7EazyHGHCpeTiiHucwroXGYdDx6pSWXMjFRJN0efiU=; b=dHiih3fxRu4MQdtPfVhJht90XELspS5MHJRUsW+PjJe5lbJmETmpIkVuXlQfeR0QICf1/m xSSgGPItny8bAbDw== To: netdev@vger.kernel.org Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Thomas Gleixner , Kurt Kanzenbach , Sebastian Andrzej Siewior Subject: [PATCH v2 net 3/7] hsr: Avoid double remove of a node. Date: Mon, 21 Nov 2022 18:46:01 +0100 Message-Id: <20221121174605.2456845-4-bigeasy@linutronix.de> In-Reply-To: <20221121174605.2456845-1-bigeasy@linutronix.de> References: <20221121174605.2456845-1-bigeasy@linutronix.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Due to the hashed-MAC optimisation one problem become visible: hsr_handle_sup_frame() walks over the list of available nodes and merges two node entries into one if based on the information in the supervision both MAC addresses belong to one node. The list-walk happens on a RCU protected list and delete operation happens under a lock. If the supervision arrives on both slave interfaces at the same time then this delete operation can occur simultaneously on two CPUs. The result is the first-CPU deletes the from the list and the second CPUs BUGs while attempting to dereference a poisoned list-entry. This happens more likely with the optimisation because a new node for the mac_B entry is created once a packet has been received and removed (merged) once the supervision frame has been received. Avoid removing/ cleaning up a hsr_node twice by adding a `removed' field which is set to true after the removal and checked before the removal. Fixes: f266a683a4804 ("net/hsr: Better frame dispatch") Signed-off-by: Sebastian Andrzej Siewior --- net/hsr/hsr_framereg.c | 16 +++++++++++----- net/hsr/hsr_framereg.h | 1 + 2 files changed, 12 insertions(+), 5 deletions(-) diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c index 9b8eaebce2549..f2dd846ff9038 100644 --- a/net/hsr/hsr_framereg.c +++ b/net/hsr/hsr_framereg.c @@ -366,9 +366,12 @@ void hsr_handle_sup_frame(struct hsr_frame_info *frame) node_real->addr_B_port = port_rcv->type; spin_lock_bh(&hsr->list_lock); - list_del_rcu(&node_curr->mac_list); + if (!node_curr->removed) { + list_del_rcu(&node_curr->mac_list); + node_curr->removed = true; + kfree_rcu(node_curr, rcu_head); + } spin_unlock_bh(&hsr->list_lock); - kfree_rcu(node_curr, rcu_head); done: /* Push back here */ @@ -539,9 +542,12 @@ void hsr_prune_nodes(struct timer_list *t) if (time_is_before_jiffies(timestamp + msecs_to_jiffies(HSR_NODE_FORGET_TIME))) { hsr_nl_nodedown(hsr, node->macaddress_A); - list_del_rcu(&node->mac_list); - /* Note that we need to free this entry later: */ - kfree_rcu(node, rcu_head); + if (!node->removed) { + list_del_rcu(&node->mac_list); + node->removed = true; + /* Note that we need to free this entry later: */ + kfree_rcu(node, rcu_head); + } } } spin_unlock_bh(&hsr->list_lock); diff --git a/net/hsr/hsr_framereg.h b/net/hsr/hsr_framereg.h index bdbb8c822ba1a..b5f902397bf1a 100644 --- a/net/hsr/hsr_framereg.h +++ b/net/hsr/hsr_framereg.h @@ -80,6 +80,7 @@ struct hsr_node { bool san_a; bool san_b; u16 seq_out[HSR_PT_PORTS]; + bool removed; struct rcu_head rcu_head; };