Return-path: Received: from smtps.newmedia-net.de ([185.84.6.167]:52723 "EHLO webmail.newmedia-net.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754917AbdIFPpD (ORCPT ); Wed, 6 Sep 2017 11:45:03 -0400 Subject: Re: hung task in mac80211 To: Matteo Croce , Johannes Berg Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <1504702728.13457.17.camel@sipsolutions.net> From: Sebastian Gottschall Message-ID: <20241e64-322a-03d3-b259-d9817c80ef53@dd-wrt.com> (sfid-20170906_174532_080957_0C98D901) Date: Wed, 6 Sep 2017 17:45:00 +0200 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: 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 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 Grüssen / Regards Sebastian Gottschall / CTO NewMedia-NET GmbH - DD-WRT Firmensitz: Berliner Ring 101, 64625 Bensheim Registergericht: Amtsgericht Darmstadt, HRB 25473 Geschäftsführer: Peter Steinhäuser, Christian Scheele http://www.dd-wrt.com email: s.gottschall@dd-wrt.com Tel.: +496251-582650 / Fax: +496251-5826565