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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 D71A9C48BD3 for ; Thu, 27 Jun 2019 00:52:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A0F4220665 for ; Thu, 27 Jun 2019 00:52:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561596720; bh=ptzxl8qxmYeGI6wR5DmA3EmQsNx61o6I1OqJVrG2zG4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=U/F8ofXTSgJ7RCzmfPQRkppkHmPCtjFEr1ZsbIF6YKXeFCzMpNEkGQT5yv3tNNmQ5 TYIolVbEyK8rYnjn1pPO/0pVw6TppDfJqR0uNWqDyj6Gqh6kuYLDRhWL1elVRsW1LE DCyWYuTP5qdRo/8/I4ZdVnq+yS2l1uxrsxl8boz4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727913AbfF0AeD (ORCPT ); Wed, 26 Jun 2019 20:34:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:38066 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726867AbfF0AeC (ORCPT ); Wed, 26 Jun 2019 20:34:02 -0400 Received: from sasha-vm.mshome.net (unknown [107.242.116.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6DDA921738; Thu, 27 Jun 2019 00:33:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561595641; bh=ptzxl8qxmYeGI6wR5DmA3EmQsNx61o6I1OqJVrG2zG4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZGn5WP1jBIZ23e0nXsBQn7dCO43PTvmZOrdHPDA1cCD5flm0mNhlwIDZkkaCLg7Bo 5rH/r+8SI4+fctTvmtp1bBb6/kmJtOZ/fjJi4RQq5OQYa5wuKDYkaKeoQbslpWvhvN BVrzWXoZ3CAVkhtzpsxNRxjFaYo3re3ml1F2z9nU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Yibo Zhao , Zhi Chen , Johannes Berg , Sasha Levin , linux-wireless@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.1 64/95] mac80211: only warn once on chanctx_conf being NULL Date: Wed, 26 Jun 2019 20:29:49 -0400 Message-Id: <20190627003021.19867-64-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190627003021.19867-1-sashal@kernel.org> References: <20190627003021.19867-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Yibo Zhao [ 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 e170f986d226..2878ea8a01fd 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