The following quirk looks like a (briefly tested with CONFIG_KMEMLEAK) fix for https://syzkaller.appspot.com/bug?extid=d5dc2801166df6d34774: diff --git a/net/mac80211/debugfs_sta.c b/net/mac80211/debugfs_sta.c index 1e9389c49a57..8224257e5d93 100644 --- a/net/mac80211/debugfs_sta.c +++ b/net/mac80211/debugfs_sta.c @@ -1284,7 +1284,9 @@ void ieee80211_sta_debugfs_add(struct sta_info *sta) void ieee80211_sta_debugfs_remove(struct sta_info *sta) { - debugfs_remove_recursive(sta->debugfs_dir); + if (!sta->debugfs_shared) + debugfs_remove_recursive(sta->debugfs_dir); + sta->debugfs_shared = false; sta->debugfs_dir = NULL; } @@ -1319,6 +1321,7 @@ void ieee80211_link_sta_debugfs_add(struct link_sta_info *link_sta) return; link_sta->debugfs_dir = link_sta->sta->debugfs_dir; + link_sta->sta->debugfs_shared = true; } DEBUGFS_ADD(ht_capa); diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h index 9195d5a2de0a..d76ba36ca794 100644 --- a/net/mac80211/sta_info.h +++ b/net/mac80211/sta_info.h @@ -708,6 +708,7 @@ struct sta_info { #ifdef CONFIG_MAC80211_DEBUGFS struct dentry *debugfs_dir; + bool debugfs_shared; #endif struct codel_params cparams; So what about managing debugfs entries wih krefs? E.g.: diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h index 9195d5a2de0a..1f4561533530 100644 --- a/net/mac80211/sta_info.h +++ b/net/mac80211/sta_info.h @@ -466,6 +466,15 @@ struct ieee80211_fragment_cache { unsigned int next; }; +#ifdef CONFIG_MAC80211_DEBUGFS + +struct sta_debugfs_entry { + struct dentry *debugfs_dir; + struct kref kref; +}; + +#endif /* CONFIG_MAC80211_DEBUGFS */ + /* * The bandwidth threshold below which the per-station CoDel parameters will be * scaled to be more lenient (to prevent starvation of slow stations). This @@ -563,7 +572,7 @@ struct link_sta_info { enum ieee80211_sta_rx_bandwidth cur_max_bandwidth; #ifdef CONFIG_MAC80211_DEBUGFS - struct dentry *debugfs_dir; + struct sta_debugfs_entry *debugfs_entry; #endif struct ieee80211_link_sta *pub; @@ -707,7 +716,7 @@ struct sta_info { struct sta_ampdu_mlme ampdu_mlme; #ifdef CONFIG_MAC80211_DEBUGFS - struct dentry *debugfs_dir; + struct sta_debugfs_entry *debugfs_entry; #endif struct codel_params cparams; Dmitry
