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author | Arnd Bergmann <arnd@arndb.de> | 2016-01-26 23:05:31 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-04-20 15:42:10 +0900 |
commit | 9da98ac378b2aaccdaa02ba10c87123eb997ff22 (patch) | |
tree | 83b7454491990cd4037408e6209aba50599c9a54 | |
parent | 7de4ebacd23756a6862e5691f326b807ccc4da91 (diff) | |
download | lwn-9da98ac378b2aaccdaa02ba10c87123eb997ff22.tar.gz lwn-9da98ac378b2aaccdaa02ba10c87123eb997ff22.zip |
mac80211: avoid excessive stack usage in sta_info
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 <arnd@arndb.de>
Fixes: 98b6218388e3 ("mac80211/cfg80211: add station events")
Fixes: 6f7a8d26e266 ("mac80211: send statistics with delete station event")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | net/mac80211/sta_info.c | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c index 4e2dbe52fd9c..67066d048e6f 100644 --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -484,11 +484,17 @@ static int sta_info_insert_finish(struct sta_info *sta) __acquires(RCU) { 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 sta_info *sta) __acquires(RCU) 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(struct sta_info *sta) { 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(struct sta_info *sta) 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); |