From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0C4CC742B9 for ; Fri, 12 Jul 2019 12:27:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B69BB216B7 for ; Fri, 12 Jul 2019 12:27:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562934459; bh=WlUI2zBQ37TDeNkfKHsamyvVlp/7aovcYPTzZDhUYwQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Jh7vVr5W6xKVkUXmxaCumUzgF+PwkIhPE8W8AjI37ZfrUjSFVJKk7OPQ/sB98GqeM IGol7W9UFrKeH3s23schXWPhD8ENGdctTdyJhGV+ekA97NzVTL9vZtAO/P6yJzQgGv 7pdCntob3IuTlkfmbAIN40I1rOe6nqJU6gkcqKGo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728103AbfGLM1i (ORCPT ); Fri, 12 Jul 2019 08:27:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:40384 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728629AbfGLM1h (ORCPT ); Fri, 12 Jul 2019 08:27:37 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 646B82084B; Fri, 12 Jul 2019 12:27:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562934456; bh=WlUI2zBQ37TDeNkfKHsamyvVlp/7aovcYPTzZDhUYwQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qyZWZjRwClSGHrSrxXliiJd4b4AWBbwRu/2pBRGRHOiirAIxF/9cfP/1w9ZnsBfQh aXCkjXZprqFUMgNEwRV7P481hCepgu+JjZOIU669hKJ2i95+8hXF30nHZp4WtraHu0 rnszobMS9BYKJBt98fbzegdqFL5CWAvD1JjBHrEw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zhi Chen , Yibo Zhao , Johannes Berg , Sasha Levin Subject: [PATCH 5.1 060/138] mac80211: only warn once on chanctx_conf being NULL Date: Fri, 12 Jul 2019 14:18:44 +0200 Message-Id: <20190712121630.981021750@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190712121628.731888964@linuxfoundation.org> References: <20190712121628.731888964@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org [ Upstream commit 563572340173865a9a356e6bb02579e6998a876d ] In multiple SSID cases, it takes time to prepare every AP interface to be ready in initializing phase. If a sta already knows everything it needs to join one of the APs and sends authentication to the AP which is not fully prepared at this point of time, AP's channel context could be NULL. As a result, warning message occurs. Even worse, if the AP is under attack via tools such as MDK3 and massive authentication requests are received in a very short time, console will be hung due to kernel warning messages. WARN_ON_ONCE() could be a better way for indicating warning messages without duplicate messages to flood the console. Johannes: We still need to address the underlying problem, but we don't really have a good handle on it yet. Suppress the worst side-effects for now. Signed-off-by: Zhi Chen Signed-off-by: Yibo Zhao [johannes: add note, change subject] Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin --- net/mac80211/ieee80211_i.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index c875d45f1e1d..4118704cb0e7 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -1434,7 +1434,7 @@ ieee80211_get_sband(struct ieee80211_sub_if_data *sdata) rcu_read_lock(); chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); - if (WARN_ON(!chanctx_conf)) { + if (WARN_ON_ONCE(!chanctx_conf)) { rcu_read_unlock(); return NULL; } -- 2.20.1