3.16.35-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Arnd Bergmann <a...@arndb.de>
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 <a...@arndb.de>
Fixes: 98b6218388e3 ("mac80211/cfg80211: add station events")
Fixes: 6f7a8d26e266 ("mac80211: send statistics with delete station event")
Signed-off-by: Johannes Berg <johannes.b...@intel.com>
[bwh: Backported to 3.16: there's only one instance to fix]
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
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
@@ -487,11 +487,17 @@ 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;
@@ -523,10 +529,9 @@ 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);
