Re: hung task in mac80211
From: Sebastian Gottschall
Date: Wed Sep 06 2017 - 11:45:13 EST
i confirm this patch fixes the issue for me as well
Am 06.09.2017 um 17:04 schrieb Matteo Croce:
On Wed, Sep 6, 2017 at 2:58 PM, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote:
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
I confirm that this patch fixes the hang too.
I'm curious to see if there are noticeable performance differences
between the two solutions.
Cheers,
--
Mit freundlichen GrÃssen / Regards
Sebastian Gottschall / CTO
NewMedia-NET GmbH - DD-WRT
Firmensitz: Berliner Ring 101, 64625 Bensheim
Registergericht: Amtsgericht Darmstadt, HRB 25473
GeschÃftsfÃhrer: Peter SteinhÃuser, Christian Scheele
http://www.dd-wrt.com
email: s.gottschall@xxxxxxxxxx
Tel.: +496251-582650 / Fax: +496251-5826565