Re: hung task in mac80211
From: Johannes Berg <johannes@sipsolutions.net>
Date: 2017-09-06 12:58:55
On Wed, 2017-09-06 at 13:57 +0200, Matteo Croce wrote:
I have an hung task on vanilla 4.13 kernel which I haven't on 4.12. The problem is present both on my AP and on my notebook, so it seems it affects AP and STA mode as well. The generated messages are: INFO: task kworker/u16:6:120 blocked for more than 120 seconds. Not tainted 4.13.0 #57 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/u16:6 D 0 120 2 0x00000000 Workqueue: phy0 ieee80211_ba_session_work [mac80211] Call Trace: ? __schedule+0x174/0x5b0 ? schedule+0x31/0x80 ? schedule_preempt_disabled+0x9/0x10 ? __mutex_lock.isra.2+0x163/0x480 ? select_task_rq_fair+0xb9f/0xc60 ? __ieee80211_start_rx_ba_session+0x135/0x4d0 [mac80211] ? __ieee80211_start_rx_ba_session+0x135/0x4d0 [mac80211]
Yeah - obviously as Stefano found, both take &sta->ampdu_mlme.mtx. Can you try this?
diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
index 2b36eff5d97e..d8d32776031e 100644
--- a/net/mac80211/agg-rx.c
+++ b/net/mac80211/agg-rx.c@@ -245,10 +245,10 @@ static void ieee80211_send_addba_resp(struct ieee80211_sub_if_data *sdata, u8 *d ieee80211_tx_skb(sdata, skb); } -void __ieee80211_start_rx_ba_session(struct sta_info *sta, - u8 dialog_token, u16 timeout, - u16 start_seq_num, u16 ba_policy, u16 tid, - u16 buf_size, bool tx, bool auto_seq) +void ___ieee80211_start_rx_ba_session(struct sta_info *sta, + u8 dialog_token, u16 timeout, + u16 start_seq_num, u16 ba_policy, u16 tid, + u16 buf_size, bool tx, bool auto_seq) { struct ieee80211_local *local = sta->sdata->local; struct tid_ampdu_rx *tid_agg_rx;
@@ -267,7 +267,7 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta, ht_dbg(sta->sdata, "STA %pM requests BA session on unsupported tid %d\n", sta->sta.addr, tid); - goto end_no_lock; + goto end; } if (!sta->sta.ht_cap.ht_supported) {
@@ -275,14 +275,14 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta, "STA %pM erroneously requests BA session on tid %d w/o QoS\n", sta->sta.addr, tid); /* send a response anyway, it's an error case if we get here */ - goto end_no_lock; + goto end; } if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) { ht_dbg(sta->sdata, "Suspend in progress - Denying ADDBA request (%pM tid %d)\n", sta->sta.addr, tid); - goto end_no_lock; + goto end; } /* sanity check for incoming parameters:
@@ -296,7 +296,7 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta, ht_dbg_ratelimited(sta->sdata, "AddBA Req with bad params from %pM on tid %u. policy %d, buffer size %d\n", sta->sta.addr, tid, ba_policy, buf_size); - goto end_no_lock; + goto end; } /* determine default buffer size */ if (buf_size == 0)
@@ -311,7 +311,6 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta, buf_size, sta->sta.addr); /* examine state machine */ - mutex_lock(&sta->ampdu_mlme.mtx); if (test_bit(tid, sta->ampdu_mlme.agg_session_valid)) { if (sta->ampdu_mlme.tid_rx_token[tid] == dialog_token) {
@@ -415,15 +414,25 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta, __clear_bit(tid, sta->ampdu_mlme.unexpected_agg); sta->ampdu_mlme.tid_rx_token[tid] = dialog_token; } - mutex_unlock(&sta->ampdu_mlme.mtx); -end_no_lock: if (tx) ieee80211_send_addba_resp(sta->sdata, sta->sta.addr, tid, dialog_token, status, 1, buf_size, timeout); } +void __ieee80211_start_rx_ba_session(struct sta_info *sta, + u8 dialog_token, u16 timeout, + u16 start_seq_num, u16 ba_policy, u16 tid, + u16 buf_size, bool tx, bool auto_seq) +{ + mutex_lock(&sta->ampdu_mlme.mtx); + ___ieee80211_start_rx_ba_session(sta, dialog_token, timeout, + start_seq_num, ba_policy, tid, + buf_size, tx, auto_seq); + mutex_unlock(&sta->ampdu_mlme.mtx); +} + void ieee80211_process_addba_request(struct ieee80211_local *local, struct sta_info *sta, struct ieee80211_mgmt *mgmt,
diff --git a/net/mac80211/ht.c b/net/mac80211/ht.c
index c92df492e898..198b2d3e56fd 100644
--- a/net/mac80211/ht.c
+++ b/net/mac80211/ht.c@@ -333,9 +333,9 @@ void ieee80211_ba_session_work(struct work_struct *work) if (test_and_clear_bit(tid, sta->ampdu_mlme.tid_rx_manage_offl)) - __ieee80211_start_rx_ba_session(sta, 0, 0, 0, 1, tid, - IEEE80211_MAX_AMPDU_BUF, - false, true); + ___ieee80211_start_rx_ba_session(sta, 0, 0, 0, 1, tid, + IEEE80211_MAX_AMPDU_BUF, + false, true); if (test_and_clear_bit(tid + IEEE80211_NUM_TIDS, sta->ampdu_mlme.tid_rx_manage_offl))
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 2197c62a0a6e..9675814f64db 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h@@ -1760,6 +1760,10 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta, u8 dialog_token, u16 timeout, u16 start_seq_num, u16 ba_policy, u16 tid, u16 buf_size, bool tx, bool auto_seq); +void ___ieee80211_start_rx_ba_session(struct sta_info *sta, + u8 dialog_token, u16 timeout, + u16 start_seq_num, u16 ba_policy, u16 tid, + u16 buf_size, bool tx, bool auto_seq); void ieee80211_sta_tear_down_BA_sessions(struct sta_info *sta, enum ieee80211_agg_stop_reason reason); void ieee80211_process_delba(struct ieee80211_sub_if_data *sdata,
johannes