69 lines
2.3 KiB
Diff
69 lines
2.3 KiB
Diff
Subject: mac80211: fix debugfs lockup
|
|
|
|
When debugfs_create_dir fails, sta_info_debugfs_add_work will not
|
|
terminate because it will find the same station again and again.
|
|
This is possible whenever debugfs fails for whatever reason; one
|
|
reason is a race condition in mac80211, unfortunately we cannot
|
|
do much about it, so just document it, it just means some station
|
|
may be missing from debugfs.
|
|
|
|
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
|
|
Cc: Robin Holt <holt@sgi.com>
|
|
---
|
|
net/mac80211/debugfs_sta.c | 11 +++++++++++
|
|
net/mac80211/sta_info.c | 7 ++++++-
|
|
net/mac80211/sta_info.h | 1 +
|
|
3 files changed, 18 insertions(+), 1 deletion(-)
|
|
|
|
--- everything.orig/net/mac80211/debugfs_sta.c 2008-10-07 20:05:29.000000000 +0200
|
|
+++ everything/net/mac80211/debugfs_sta.c 2008-10-07 20:06:39.000000000 +0200
|
|
@@ -249,11 +249,22 @@ void ieee80211_sta_debugfs_add(struct st
|
|
DECLARE_MAC_BUF(mbuf);
|
|
u8 *mac;
|
|
|
|
+ sta->debugfs.add_has_run = true;
|
|
+
|
|
if (!stations_dir)
|
|
return;
|
|
|
|
mac = print_mac(mbuf, sta->sta.addr);
|
|
|
|
+ /*
|
|
+ * This might fail due to a race condition:
|
|
+ * When mac80211 unlinks a station, the debugfs entries
|
|
+ * remain, but it is already possible to link a new
|
|
+ * station with the same address which triggers adding
|
|
+ * it to debugfs; therefore, if the old station isn't
|
|
+ * destroyed quickly enough the old station's debugfs
|
|
+ * dir might still be around.
|
|
+ */
|
|
sta->debugfs.dir = debugfs_create_dir(mac, stations_dir);
|
|
if (!sta->debugfs.dir)
|
|
return;
|
|
--- everything.orig/net/mac80211/sta_info.c 2008-10-07 20:05:29.000000000 +0200
|
|
+++ everything/net/mac80211/sta_info.c 2008-10-07 20:06:39.000000000 +0200
|
|
@@ -635,7 +635,12 @@ static void sta_info_debugfs_add_work(st
|
|
|
|
spin_lock_irqsave(&local->sta_lock, flags);
|
|
list_for_each_entry(tmp, &local->sta_list, list) {
|
|
- if (!tmp->debugfs.dir) {
|
|
+ /*
|
|
+ * debugfs.add_has_run will be set by
|
|
+ * ieee80211_sta_debugfs_add regardless
|
|
+ * of what else it does.
|
|
+ */
|
|
+ if (!tmp->debugfs.add_has_run) {
|
|
sta = tmp;
|
|
__sta_info_pin(sta);
|
|
break;
|
|
--- everything.orig/net/mac80211/sta_info.h 2008-10-07 20:05:29.000000000 +0200
|
|
+++ everything/net/mac80211/sta_info.h 2008-10-07 20:06:39.000000000 +0200
|
|
@@ -300,6 +300,7 @@ struct sta_info {
|
|
struct dentry *inactive_ms;
|
|
struct dentry *last_seq_ctrl;
|
|
struct dentry *agg_status;
|
|
+ bool add_has_run;
|
|
} debugfs;
|
|
#endif
|
|
|