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 C2A1CC48BD6 for ; Thu, 27 Jun 2019 00:44:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F5EA20815 for ; Thu, 27 Jun 2019 00:44:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561596260; bh=aAb+mwg+i2aAD0mzdzIduCf6f+nnagV6YxxTGDKKfMU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=UbzULue4A5Te6surbGyX2xKk2Us9/8oad+Mhhtas17ktuCVIE4kDWU/sqicnD3lHl Xe01/WAguVhDPZELv5POfflPaN42McwNVIKqXh7gctDb64+VyGZUjXDa7bQ8rd9iUA +O7YXKIQIr4w2cARUqtOMbA8lACdTsvxDkgZBgGI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729699AbfF0AmX (ORCPT ); Wed, 26 Jun 2019 20:42:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:46188 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729125AbfF0AmX (ORCPT ); Wed, 26 Jun 2019 20:42:23 -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 A025A21871; Thu, 27 Jun 2019 00:42:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561596141; bh=aAb+mwg+i2aAD0mzdzIduCf6f+nnagV6YxxTGDKKfMU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NzimBX28XWkwYXukKg3HelW+sY3BPi+wcjcRvmar9x54YRepBQLHyviKXQBU133Ql NqEVqhYQ9f7ilC8GXxmXrTePvxd4WFdifWeMNDY+oOt5JFKSF4JvQ7q2OOog/IfHmw ZORFMV9nDROpTqYcwYmSdt/jzqk95LN3wXUfuhd8= 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 4.9 17/21] mac80211: only warn once on chanctx_conf being NULL Date: Wed, 26 Jun 2019 20:41:17 -0400 Message-Id: <20190627004122.21671-17-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190627004122.21671-1-sashal@kernel.org> References: <20190627004122.21671-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@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 8a690ebd7374..6708de10a3e5 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -1403,7 +1403,7 @@ 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