Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932289AbcDRCjS (ORCPT ); Sun, 17 Apr 2016 22:39:18 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:36936 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932242AbcDRCjI (ORCPT ); Sun, 17 Apr 2016 22:39:08 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Arnd Bergmann , Johannes Berg Subject: [PATCH 4.4 099/137] mac80211: avoid excessive stack usage in sta_info Date: Mon, 18 Apr 2016 11:29:21 +0900 Message-Id: <20160418022513.795701801@linuxfoundation.org> X-Mailer: git-send-email 2.8.0 In-Reply-To: <20160418022507.236379264@linuxfoundation.org> References: <20160418022507.236379264@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3288 Lines: 96 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnd Bergmann commit 0ef049dc1167fe834d0ad5d63f89eddc5c70f6e4 upstream. When CONFIG_OPTIMIZE_INLINING is set, the sta_info_insert_finish function consumes more stack than normally, exceeding the 1024 byte limit on ARM: net/mac80211/sta_info.c: In function 'sta_info_insert_finish': net/mac80211/sta_info.c:561:1: error: the frame size of 1080 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] It turns out that there are two functions that put a 'struct station_info' on the stack: __sta_info_destroy_part2 and sta_info_insert_finish, and this structure alone requires up to 792 bytes. Hoping that both are called rarely enough, this replaces the on-stack structure with a dynamic allocation, which unfortunately requires some suboptimal error handling for out-of-memory. The __sta_info_destroy_part2 function is actually affected by the stack usage twice because it calls cfg80211_del_sta_sinfo(), which has another instance of struct station_info on its stack. Signed-off-by: Arnd Bergmann Fixes: 98b6218388e3 ("mac80211/cfg80211: add station events") Fixes: 6f7a8d26e266 ("mac80211: send statistics with delete station event") Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/mac80211/sta_info.c | 24 ++++++++++++++++-------- 1 file changed, 16 insertions(+), 8 deletions(-) --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -484,11 +484,17 @@ static int sta_info_insert_finish(struct { struct ieee80211_local *local = sta->local; struct ieee80211_sub_if_data *sdata = sta->sdata; - struct station_info sinfo; + struct station_info *sinfo; int err = 0; lockdep_assert_held(&local->sta_mtx); + sinfo = kzalloc(sizeof(struct station_info), GFP_KERNEL); + if (!sinfo) { + err = -ENOMEM; + goto out_err; + } + /* check if STA exists already */ if (sta_info_get_bss(sdata, sta->sta.addr)) { err = -EEXIST; @@ -522,10 +528,9 @@ static int sta_info_insert_finish(struct ieee80211_sta_debugfs_add(sta); rate_control_add_sta_debugfs(sta); - memset(&sinfo, 0, sizeof(sinfo)); - sinfo.filled = 0; - sinfo.generation = local->sta_generation; - cfg80211_new_sta(sdata->dev, sta->sta.addr, &sinfo, GFP_KERNEL); + sinfo->generation = local->sta_generation; + cfg80211_new_sta(sdata->dev, sta->sta.addr, sinfo, GFP_KERNEL); + kfree(sinfo); sta_dbg(sdata, "Inserted STA %pM\n", sta->sta.addr); @@ -885,7 +890,7 @@ static void __sta_info_destroy_part2(str { struct ieee80211_local *local = sta->local; struct ieee80211_sub_if_data *sdata = sta->sdata; - struct station_info sinfo = {}; + struct station_info *sinfo; int ret; /* @@ -923,8 +928,11 @@ static void __sta_info_destroy_part2(str sta_dbg(sdata, "Removed STA %pM\n", sta->sta.addr); - sta_set_sinfo(sta, &sinfo); - cfg80211_del_sta_sinfo(sdata->dev, sta->sta.addr, &sinfo, GFP_KERNEL); + sinfo = kzalloc(sizeof(*sinfo), GFP_KERNEL); + if (sinfo) + sta_set_sinfo(sta, sinfo); + cfg80211_del_sta_sinfo(sdata->dev, sta->sta.addr, sinfo, GFP_KERNEL); + kfree(sinfo); rate_control_remove_sta_debugfs(sta); ieee80211_sta_debugfs_remove(sta);