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* [PATCH] mt76: fix schedule while atomic in mt76x02_reset_state
       [not found] <cover.1552251427.git.lorenzo@kernel.org>
@ 2019-03-10 22:47 ` Lorenzo Bianconi
  2019-03-11 10:07   ` Felix Fietkau
  0 siblings, 1 reply; 3+ messages in thread
From: Lorenzo Bianconi @ 2019-03-10 22:47 UTC (permalink / raw)
  To: nbd; +Cc: linux-wireless, sgruszka, lorenzo.bianconi

Fix following schedule while atomic mt76x02_reset_state
since synchronize_rcu is run inside a RCU section

[44036.944222] mt76x2e 0000:06:00.0: MCU message 31 (seq 3) timed out
[44036.944281] BUG: sleeping function called from invalid context at kernel/rcu/tree_exp.h:818
[44036.944284] in_atomic(): 1, irqs_disabled(): 0, pid: 28066, name: kworker/u4:1
[44036.944287] INFO: lockdep is turned off.
[44036.944292] CPU: 1 PID: 28066 Comm: kworker/u4:1 Tainted: G        W         5.0.0-rc7-wdn-t1+ #7
[44036.944294] Hardware name: Dell Inc. Studio XPS 1340/0K183D, BIOS A11 09/08/2009
[44036.944305] Workqueue: phy1 mt76x02_wdt_work [mt76x02_lib]
[44036.944308] Call Trace:
[44036.944317]  dump_stack+0x67/0x90
[44036.944322]  ___might_sleep.cold.88+0x9f/0xaf
[44036.944327]  rcu_blocking_is_gp+0x13/0x50
[44036.944330]  synchronize_rcu+0x17/0x80
[44036.944337]  mt76_sta_state+0x138/0x1d0 [mt76]
[44036.944349]  mt76x02_wdt_work+0x1c9/0x610 [mt76x02_lib]
[44036.944355]  process_one_work+0x2a5/0x620
[44036.944361]  worker_thread+0x35/0x3e0
[44036.944368]  kthread+0x11c/0x140
[44036.944376]  ret_from_fork+0x3a/0x50
[44036.944384] BUG: scheduling while atomic: kworker/u4:1/28066/0x00000002
[44036.944387] INFO: lockdep is turned off.
[44036.944389] Modules linked in: cmac ctr ccm af_packet snd_hda_codec_hdmi

Introduce __mt76_sta_remove in order to run sta_remove without holding dev->mutex.
Move __mt76_sta_remove outside RCU section in mt76x02_reset_state

Fixes: e4ebb8b403d1 ("mt76: mt76x2: implement full device restart on watchdog reset")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/wireless/mediatek/mt76/mac80211.c  | 18 +++++++++++-------
 drivers/net/wireless/mediatek/mt76/mt76.h      |  2 ++
 .../net/wireless/mediatek/mt76/mt76x02_mmio.c  | 14 ++++++--------
 3 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mac80211.c b/drivers/net/wireless/mediatek/mt76/mac80211.c
index a033745adb2f..bde52943ecaf 100644
--- a/drivers/net/wireless/mediatek/mt76/mac80211.c
+++ b/drivers/net/wireless/mediatek/mt76/mac80211.c
@@ -679,19 +679,15 @@ mt76_sta_add(struct mt76_dev *dev, struct ieee80211_vif *vif,
 	return ret;
 }
 
-static void
-mt76_sta_remove(struct mt76_dev *dev, struct ieee80211_vif *vif,
-	        struct ieee80211_sta *sta)
+void __mt76_sta_remove(struct mt76_dev *dev, struct ieee80211_vif *vif,
+		       struct ieee80211_sta *sta)
 {
 	struct mt76_wcid *wcid = (struct mt76_wcid *)sta->drv_priv;
-	int idx = wcid->idx;
-	int i;
+	int i, idx = wcid->idx;
 
 	rcu_assign_pointer(dev->wcid[idx], NULL);
 	synchronize_rcu();
 
-	mutex_lock(&dev->mutex);
-
 	if (dev->drv->sta_remove)
 		dev->drv->sta_remove(dev, vif, sta);
 
@@ -699,7 +695,15 @@ mt76_sta_remove(struct mt76_dev *dev, struct ieee80211_vif *vif,
 	for (i = 0; i < ARRAY_SIZE(sta->txq); i++)
 		mt76_txq_remove(dev, sta->txq[i]);
 	mt76_wcid_free(dev->wcid_mask, idx);
+}
+EXPORT_SYMBOL_GPL(__mt76_sta_remove);
 
+static void
+mt76_sta_remove(struct mt76_dev *dev, struct ieee80211_vif *vif,
+	        struct ieee80211_sta *sta)
+{
+	mutex_lock(&dev->mutex);
+	__mt76_sta_remove(dev, vif, sta);
 	mutex_unlock(&dev->mutex);
 }
 
diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
index 477027bb9aaf..eb72e4bf3db6 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76.h
@@ -697,6 +697,8 @@ int mt76_sta_state(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 		   struct ieee80211_sta *sta,
 		   enum ieee80211_sta_state old_state,
 		   enum ieee80211_sta_state new_state);
+void __mt76_sta_remove(struct mt76_dev *dev, struct ieee80211_vif *vif,
+		       struct ieee80211_sta *sta);
 
 struct ieee80211_sta *mt76_rx_convert(struct sk_buff *skb);
 
diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c b/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c
index 6a34a6afcfe4..898afcbcdf52 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c
@@ -419,6 +419,7 @@ static void mt76x02_key_sync(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 	mt76x02_mac_wcid_sync_pn(dev, wcid->idx, key);
 }
 
+/* need to run with mt76.mutex held */
 static void mt76x02_reset_state(struct mt76x02_dev *dev)
 {
 	int i;
@@ -426,11 +427,11 @@ static void mt76x02_reset_state(struct mt76x02_dev *dev)
 	clear_bit(MT76_STATE_RUNNING, &dev->mt76.state);
 
 	rcu_read_lock();
-
 	ieee80211_iter_keys_rcu(dev->mt76.hw, NULL, mt76x02_key_sync, NULL);
+	rcu_read_unlock();
 
 	for (i = 0; i < ARRAY_SIZE(dev->mt76.wcid); i++) {
-		struct mt76_wcid *wcid = rcu_dereference(dev->mt76.wcid[i]);
+		struct mt76_wcid *wcid = dev->mt76.wcid[i];
 		struct mt76x02_sta *msta;
 		struct ieee80211_sta *sta;
 		struct ieee80211_vif *vif;
@@ -445,13 +446,10 @@ static void mt76x02_reset_state(struct mt76x02_dev *dev)
 		priv = msta->vif;
 		vif = container_of(priv, struct ieee80211_vif, drv_priv);
 
-		mt76_sta_state(dev->mt76.hw, vif, sta,
-			       IEEE80211_STA_NONE, IEEE80211_STA_NOTEXIST);
+		__mt76_sta_remove(&dev->mt76, vif, sta);
 		memset(msta, 0, sizeof(*msta));
 	}
 
-	rcu_read_unlock();
-
 	dev->vif_mask = 0;
 	dev->beacon_mask = 0;
 }
@@ -471,11 +469,11 @@ static void mt76x02_watchdog_reset(struct mt76x02_dev *dev)
 	for (i = 0; i < ARRAY_SIZE(dev->mt76.napi); i++)
 		napi_disable(&dev->mt76.napi[i]);
 
+	mutex_lock(&dev->mt76.mutex);
+
 	if (restart)
 		mt76x02_reset_state(dev);
 
-	mutex_lock(&dev->mt76.mutex);
-
 	if (dev->beacon_mask)
 		mt76_clear(dev, MT_BEACON_TIME_CFG,
 			   MT_BEACON_TIME_CFG_BEACON_TX |
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH] mt76: fix schedule while atomic in mt76x02_reset_state
  2019-03-10 22:47 ` [PATCH] mt76: fix schedule while atomic in mt76x02_reset_state Lorenzo Bianconi
@ 2019-03-11 10:07   ` Felix Fietkau
  2019-03-11 10:11     ` Lorenzo Bianconi
  0 siblings, 1 reply; 3+ messages in thread
From: Felix Fietkau @ 2019-03-11 10:07 UTC (permalink / raw)
  To: Lorenzo Bianconi; +Cc: linux-wireless, sgruszka, lorenzo.bianconi

On 2019-03-10 23:47, Lorenzo Bianconi wrote:
> Fix following schedule while atomic mt76x02_reset_state
> since synchronize_rcu is run inside a RCU section
> 
> [44036.944222] mt76x2e 0000:06:00.0: MCU message 31 (seq 3) timed out
> [44036.944281] BUG: sleeping function called from invalid context at kernel/rcu/tree_exp.h:818
> [44036.944284] in_atomic(): 1, irqs_disabled(): 0, pid: 28066, name: kworker/u4:1
> [44036.944287] INFO: lockdep is turned off.
> [44036.944292] CPU: 1 PID: 28066 Comm: kworker/u4:1 Tainted: G        W         5.0.0-rc7-wdn-t1+ #7
> [44036.944294] Hardware name: Dell Inc. Studio XPS 1340/0K183D, BIOS A11 09/08/2009
> [44036.944305] Workqueue: phy1 mt76x02_wdt_work [mt76x02_lib]
> [44036.944308] Call Trace:
> [44036.944317]  dump_stack+0x67/0x90
> [44036.944322]  ___might_sleep.cold.88+0x9f/0xaf
> [44036.944327]  rcu_blocking_is_gp+0x13/0x50
> [44036.944330]  synchronize_rcu+0x17/0x80
> [44036.944337]  mt76_sta_state+0x138/0x1d0 [mt76]
> [44036.944349]  mt76x02_wdt_work+0x1c9/0x610 [mt76x02_lib]
> [44036.944355]  process_one_work+0x2a5/0x620
> [44036.944361]  worker_thread+0x35/0x3e0
> [44036.944368]  kthread+0x11c/0x140
> [44036.944376]  ret_from_fork+0x3a/0x50
> [44036.944384] BUG: scheduling while atomic: kworker/u4:1/28066/0x00000002
> [44036.944387] INFO: lockdep is turned off.
> [44036.944389] Modules linked in: cmac ctr ccm af_packet snd_hda_codec_hdmi
> 
> Introduce __mt76_sta_remove in order to run sta_remove without holding dev->mutex.
> Move __mt76_sta_remove outside RCU section in mt76x02_reset_state
> 
> Fixes: e4ebb8b403d1 ("mt76: mt76x2: implement full device restart on watchdog reset")
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c b/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c
> index 6a34a6afcfe4..898afcbcdf52 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c
> @@ -419,6 +419,7 @@ static void mt76x02_key_sync(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
>  	mt76x02_mac_wcid_sync_pn(dev, wcid->idx, key);
>  }
>  
> +/* need to run with mt76.mutex held */
>  static void mt76x02_reset_state(struct mt76x02_dev *dev)
You can replace that comment with a call to lockdep_assert_held in the
function.

> @@ -426,11 +427,11 @@ static void mt76x02_reset_state(struct mt76x02_dev *dev)
>  	clear_bit(MT76_STATE_RUNNING, &dev->mt76.state);
>  
>  	rcu_read_lock();
> -
>  	ieee80211_iter_keys_rcu(dev->mt76.hw, NULL, mt76x02_key_sync, NULL);
> +	rcu_read_unlock();
>  
>  	for (i = 0; i < ARRAY_SIZE(dev->mt76.wcid); i++) {
> -		struct mt76_wcid *wcid = rcu_dereference(dev->mt76.wcid[i]);
> +		struct mt76_wcid *wcid = dev->mt76.wcid[i];
This should use rcu_dereference_protected() instead of accessing the
pointer directly.

Thanks,

- Felix

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH] mt76: fix schedule while atomic in mt76x02_reset_state
  2019-03-11 10:07   ` Felix Fietkau
@ 2019-03-11 10:11     ` Lorenzo Bianconi
  0 siblings, 0 replies; 3+ messages in thread
From: Lorenzo Bianconi @ 2019-03-11 10:11 UTC (permalink / raw)
  To: Felix Fietkau; +Cc: Lorenzo Bianconi, linux-wireless, sgruszka

[-- Attachment #1: Type: text/plain, Size: 3103 bytes --]

> On 2019-03-10 23:47, Lorenzo Bianconi wrote:
> > Fix following schedule while atomic mt76x02_reset_state
> > since synchronize_rcu is run inside a RCU section
> > 
> > [44036.944222] mt76x2e 0000:06:00.0: MCU message 31 (seq 3) timed out
> > [44036.944281] BUG: sleeping function called from invalid context at kernel/rcu/tree_exp.h:818
> > [44036.944284] in_atomic(): 1, irqs_disabled(): 0, pid: 28066, name: kworker/u4:1
> > [44036.944287] INFO: lockdep is turned off.
> > [44036.944292] CPU: 1 PID: 28066 Comm: kworker/u4:1 Tainted: G        W         5.0.0-rc7-wdn-t1+ #7
> > [44036.944294] Hardware name: Dell Inc. Studio XPS 1340/0K183D, BIOS A11 09/08/2009
> > [44036.944305] Workqueue: phy1 mt76x02_wdt_work [mt76x02_lib]
> > [44036.944308] Call Trace:
> > [44036.944317]  dump_stack+0x67/0x90
> > [44036.944322]  ___might_sleep.cold.88+0x9f/0xaf
> > [44036.944327]  rcu_blocking_is_gp+0x13/0x50
> > [44036.944330]  synchronize_rcu+0x17/0x80
> > [44036.944337]  mt76_sta_state+0x138/0x1d0 [mt76]
> > [44036.944349]  mt76x02_wdt_work+0x1c9/0x610 [mt76x02_lib]
> > [44036.944355]  process_one_work+0x2a5/0x620
> > [44036.944361]  worker_thread+0x35/0x3e0
> > [44036.944368]  kthread+0x11c/0x140
> > [44036.944376]  ret_from_fork+0x3a/0x50
> > [44036.944384] BUG: scheduling while atomic: kworker/u4:1/28066/0x00000002
> > [44036.944387] INFO: lockdep is turned off.
> > [44036.944389] Modules linked in: cmac ctr ccm af_packet snd_hda_codec_hdmi
> > 
> > Introduce __mt76_sta_remove in order to run sta_remove without holding dev->mutex.
> > Move __mt76_sta_remove outside RCU section in mt76x02_reset_state
> > 
> > Fixes: e4ebb8b403d1 ("mt76: mt76x2: implement full device restart on watchdog reset")
> > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> > diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c b/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c
> > index 6a34a6afcfe4..898afcbcdf52 100644
> > --- a/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c
> > +++ b/drivers/net/wireless/mediatek/mt76/mt76x02_mmio.c
> > @@ -419,6 +419,7 @@ static void mt76x02_key_sync(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
> >  	mt76x02_mac_wcid_sync_pn(dev, wcid->idx, key);
> >  }
> >  
> > +/* need to run with mt76.mutex held */
> >  static void mt76x02_reset_state(struct mt76x02_dev *dev)
> You can replace that comment with a call to lockdep_assert_held in the
> function.
> 
> > @@ -426,11 +427,11 @@ static void mt76x02_reset_state(struct mt76x02_dev *dev)
> >  	clear_bit(MT76_STATE_RUNNING, &dev->mt76.state);
> >  
> >  	rcu_read_lock();
> > -
> >  	ieee80211_iter_keys_rcu(dev->mt76.hw, NULL, mt76x02_key_sync, NULL);
> > +	rcu_read_unlock();
> >  
> >  	for (i = 0; i < ARRAY_SIZE(dev->mt76.wcid); i++) {
> > -		struct mt76_wcid *wcid = rcu_dereference(dev->mt76.wcid[i]);
> > +		struct mt76_wcid *wcid = dev->mt76.wcid[i];
> This should use rcu_dereference_protected() instead of accessing the
> pointer directly.
> 

ack, I will fix them in v2.

Regards,
Lorenzo

> Thanks,
> 
> - Felix

[-- Attachment #2: signature.asc --]
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^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2019-03-11 10:11 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
     [not found] <cover.1552251427.git.lorenzo@kernel.org>
2019-03-10 22:47 ` [PATCH] mt76: fix schedule while atomic in mt76x02_reset_state Lorenzo Bianconi
2019-03-11 10:07   ` Felix Fietkau
2019-03-11 10:11     ` Lorenzo Bianconi

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