From b3fa0241e2faaf4080f4903c0547949ebcddbc6b Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Sun, 27 Mar 2022 00:05:49 +0100 Subject: [PATCH] mac80211: backport tx queueing bugfixes add a bug fix for a rare crash Re-introduce the queue wake fix that was reverted due to a regression, but this time with the follow-up fixes that take care of the regression. Signed-off-by: Felix Fietkau (cherry picked from commit 9a93b62f315ad4c9f021c414ed80ba337ab4a01e) (cherry-picked from commit 8b804cae5e039142bc63896a75f15146eca3bebc) (cherry-picked from commit 8b06e06832ebe757246582b65306ad2a2537741f) --- ...wake-queues-on-a-vif-that-is-being-s.patch | 38 +++++++++++++++ ...-not-abuse-fq.lock-in-ieee80211_do_s.patch | 46 ++++++++++++++++++ ...dlock-Don-t-start-TX-while-holding-f.patch | 40 ++++++++++++++++ ...vif-queues-are-operational-after-sta.patch | 47 +++++++++++++++++++ 4 files changed, 171 insertions(+) create mode 100644 package/kernel/mac80211/patches/subsys/328-mac80211-do-not-wake-queues-on-a-vif-that-is-being-s.patch create mode 100644 package/kernel/mac80211/patches/subsys/340-wifi-mac80211-do-not-abuse-fq.lock-in-ieee80211_do_s.patch create mode 100644 package/kernel/mac80211/patches/subsys/341-mac80211-Fix-deadlock-Don-t-start-TX-while-holding-f.patch create mode 100644 package/kernel/mac80211/patches/subsys/342-mac80211-Ensure-vif-queues-are-operational-after-sta.patch diff --git a/package/kernel/mac80211/patches/subsys/328-mac80211-do-not-wake-queues-on-a-vif-that-is-being-s.patch b/package/kernel/mac80211/patches/subsys/328-mac80211-do-not-wake-queues-on-a-vif-that-is-being-s.patch new file mode 100644 index 0000000000..f0150ddef0 --- /dev/null +++ b/package/kernel/mac80211/patches/subsys/328-mac80211-do-not-wake-queues-on-a-vif-that-is-being-s.patch @@ -0,0 +1,38 @@ +From: Felix Fietkau +Date: Sat, 26 Mar 2022 23:58:35 +0100 +Subject: [PATCH] mac80211: do not wake queues on a vif that is being stopped + +When a vif is being removed and sdata->bss is cleared, __ieee80211_wake_txqs +can still be called on it, which crashes as soon as sdata->bss is being +dereferenced. +To fix this properly, check for SDATA_STATE_RUNNING before waking queues, +and take the fq lock when setting it (to ensure that __ieee80211_wake_txqs +observes the change when running on a different CPU + +Signed-off-by: Felix Fietkau +--- + +--- a/net/mac80211/iface.c ++++ b/net/mac80211/iface.c +@@ -377,7 +377,9 @@ static void ieee80211_do_stop(struct iee + bool cancel_scan; + struct cfg80211_nan_func *func; + ++ spin_lock_bh(&local->fq.lock); + clear_bit(SDATA_STATE_RUNNING, &sdata->state); ++ spin_unlock_bh(&local->fq.lock); + + cancel_scan = rcu_access_pointer(local->scan_sdata) == sdata; + if (cancel_scan) +--- a/net/mac80211/util.c ++++ b/net/mac80211/util.c +@@ -301,6 +301,9 @@ static void __ieee80211_wake_txqs(struct + local_bh_disable(); + spin_lock(&fq->lock); + ++ if (!test_bit(SDATA_STATE_RUNNING, &sdata->state)) ++ goto out; ++ + if (sdata->vif.type == NL80211_IFTYPE_AP) + ps = &sdata->bss->ps; + diff --git a/package/kernel/mac80211/patches/subsys/340-wifi-mac80211-do-not-abuse-fq.lock-in-ieee80211_do_s.patch b/package/kernel/mac80211/patches/subsys/340-wifi-mac80211-do-not-abuse-fq.lock-in-ieee80211_do_s.patch new file mode 100644 index 0000000000..82243f1d98 --- /dev/null +++ b/package/kernel/mac80211/patches/subsys/340-wifi-mac80211-do-not-abuse-fq.lock-in-ieee80211_do_s.patch @@ -0,0 +1,46 @@ +From aa40d5a43526cca9439a2b45fcfdcd016594dece Mon Sep 17 00:00:00 2001 +From: Tetsuo Handa +Date: Sun, 17 Jul 2022 21:21:52 +0900 +Subject: [PATCH] wifi: mac80211: do not abuse fq.lock in ieee80211_do_stop() +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +lockdep complains use of uninitialized spinlock at ieee80211_do_stop() [1], +for commit f856373e2f31ffd3 ("wifi: mac80211: do not wake queues on a vif +that is being stopped") guards clear_bit() using fq.lock even before +fq_init() from ieee80211_txq_setup_flows() initializes this spinlock. + +According to discussion [2], Toke was not happy with expanding usage of +fq.lock. Since __ieee80211_wake_txqs() is called under RCU read lock, we +can instead use synchronize_rcu() for flushing ieee80211_wake_txqs(). + +Link: https://syzkaller.appspot.com/bug?extid=eceab52db7c4b961e9d6 [1] +Link: https://lkml.kernel.org/r/874k0zowh2.fsf@toke.dk [2] +Reported-by: syzbot +Signed-off-by: Tetsuo Handa +Fixes: f856373e2f31ffd3 ("wifi: mac80211: do not wake queues on a vif that is being stopped") +Tested-by: syzbot +Acked-by: Toke Høiland-Jørgensen +Signed-off-by: Kalle Valo +Link: https://lore.kernel.org/r/9cc9b81d-75a3-3925-b612-9d0ad3cab82b@I-love.SAKURA.ne.jp +[ pick up commit 3598cb6e1862 ("wifi: mac80211: do not abuse fq.lock in ieee80211_do_stop()") from -next] +Link: https://lore.kernel.org/all/87o7xcq6qt.fsf@kernel.org/ +Signed-off-by: Jakub Kicinski +--- + net/mac80211/iface.c | 3 +-- + 1 file changed, 1 insertion(+), 2 deletions(-) + +--- a/net/mac80211/iface.c ++++ b/net/mac80211/iface.c +@@ -377,9 +377,8 @@ static void ieee80211_do_stop(struct iee + bool cancel_scan; + struct cfg80211_nan_func *func; + +- spin_lock_bh(&local->fq.lock); + clear_bit(SDATA_STATE_RUNNING, &sdata->state); +- spin_unlock_bh(&local->fq.lock); ++ synchronize_rcu(); /* flush _ieee80211_wake_txqs() */ + + cancel_scan = rcu_access_pointer(local->scan_sdata) == sdata; + if (cancel_scan) diff --git a/package/kernel/mac80211/patches/subsys/341-mac80211-Fix-deadlock-Don-t-start-TX-while-holding-f.patch b/package/kernel/mac80211/patches/subsys/341-mac80211-Fix-deadlock-Don-t-start-TX-while-holding-f.patch new file mode 100644 index 0000000000..8c56acbf88 --- /dev/null +++ b/package/kernel/mac80211/patches/subsys/341-mac80211-Fix-deadlock-Don-t-start-TX-while-holding-f.patch @@ -0,0 +1,40 @@ +From: Alexander Wetzel +Date: Thu, 15 Sep 2022 14:41:20 +0200 +Subject: [PATCH] mac80211: Fix deadlock: Don't start TX while holding + fq->lock + +ieee80211_txq_purge() calls fq_tin_reset() and +ieee80211_purge_tx_queue(); Both are then calling +ieee80211_free_txskb(). Which can decide to TX the skb again. + +There are at least two ways to get a deadlock: + +1) When we have a TDLS teardown packet queued in either tin or frags + ieee80211_tdls_td_tx_handle() will call ieee80211_subif_start_xmit() + while we still hold fq->lock. ieee80211_txq_enqueue() will thus + deadlock. + +2) A variant of the above happens if aggregation is up and running: + In that case ieee80211_iface_work() will deadlock with the original + task: The original tasks already holds fq->lock and tries to get + sta->lock after kicking off ieee80211_iface_work(). But the worker + can get sta->lock prior to the original task and will then spin for + fq->lock. + +Avoid these deadlocks by not sending out any skbs when called via +ieee80211_free_txskb(). + +Signed-off-by: Alexander Wetzel +--- + +--- a/net/mac80211/status.c ++++ b/net/mac80211/status.c +@@ -698,7 +698,7 @@ static void ieee80211_report_used_skb(st + + if (!sdata) { + skb->dev = NULL; +- } else { ++ } else if (!dropped) { + unsigned int hdr_size = + ieee80211_hdrlen(hdr->frame_control); + diff --git a/package/kernel/mac80211/patches/subsys/342-mac80211-Ensure-vif-queues-are-operational-after-sta.patch b/package/kernel/mac80211/patches/subsys/342-mac80211-Ensure-vif-queues-are-operational-after-sta.patch new file mode 100644 index 0000000000..4310329319 --- /dev/null +++ b/package/kernel/mac80211/patches/subsys/342-mac80211-Ensure-vif-queues-are-operational-after-sta.patch @@ -0,0 +1,47 @@ +From: Alexander Wetzel +Date: Thu, 15 Sep 2022 15:09:46 +0200 +Subject: [PATCH] mac80211: Ensure vif queues are operational after start + +Make sure local->queue_stop_reasons and vif.txqs_stopped stay in sync. + +When a new vif is created the queues may end up in an inconsistent state +and be inoperable: +Communication not using iTXQ will work, allowing to e.g. complete the +association. But the 4-way handshake will time out. The sta will not +send out any skbs queued in iTXQs. + +All normal attempts to start the queues will fail when reaching this +state. +local->queue_stop_reasons will have marked all queues as operational but +vif.txqs_stopped will still be set, creating an inconsistent internal +state. + +In reality this seems to be race between the mac80211 function +ieee80211_do_open() setting SDATA_STATE_RUNNING and the wake_txqs_tasklet: +Depending on the driver and the timing the queues may end up to be +operational or not. + +Cc: stable@vger.kernel.org +Fixes: f856373e2f31 ("wifi: mac80211: do not wake queues on a vif that is being stopped") +Signed-off-by: Alexander Wetzel +--- + +--- a/net/mac80211/util.c ++++ b/net/mac80211/util.c +@@ -301,14 +301,14 @@ static void __ieee80211_wake_txqs(struct + local_bh_disable(); + spin_lock(&fq->lock); + ++ sdata->vif.txqs_stopped[ac] = false; ++ + if (!test_bit(SDATA_STATE_RUNNING, &sdata->state)) + goto out; + + if (sdata->vif.type == NL80211_IFTYPE_AP) + ps = &sdata->bss->ps; + +- sdata->vif.txqs_stopped[ac] = false; +- + list_for_each_entry_rcu(sta, &local->sta_list, list) { + if (sdata != sta->sdata) + continue; -- 2.30.2