2009-08-20 17:46:24

by Johannes Berg

[permalink] [raw]
Subject: [PATCH] mac80211: fix configure_filter invocation after stop

Since configure_filter can sleep now, any multicast
configuration needed to be postponed to a work struct.
This, however, lead to a problem that we could queue
the work, stop the device and then afterwards invoke
configure_filter which may lead to driver hangs and is
a bug. To fix this, we can just cancel the filter work
since it's unnecessary to do after stopping the hw.

Since there are various places that call drv_stop, and
two of them do very similar things, the code for them
can be put into a shared function at the same time.

Signed-off-by: Johannes Berg <[email protected]>
Reported-by: Lennert Buytenhek <[email protected]>
---
net/mac80211/ieee80211_i.h | 1 +
net/mac80211/iface.c | 6 +-----
net/mac80211/pm.c | 11 +----------
net/mac80211/util.c | 10 ++++++++++
4 files changed, 13 insertions(+), 15 deletions(-)

--- wireless-testing.orig/net/mac80211/iface.c 2009-08-20 13:30:41.000000000 +0200
+++ wireless-testing/net/mac80211/iface.c 2009-08-20 14:55:48.000000000 +0200
@@ -552,11 +552,7 @@ static int ieee80211_stop(struct net_dev
ieee80211_recalc_ps(local, -1);

if (local->open_count == 0) {
- drv_stop(local);
-
- ieee80211_led_radio(local, false);
-
- flush_workqueue(local->workqueue);
+ ieee80211_stop_device(local);

tasklet_disable(&local->tx_pending_tasklet);
tasklet_disable(&local->tasklet);
--- wireless-testing.orig/net/mac80211/ieee80211_i.h 2009-08-20 14:53:42.000000000 +0200
+++ wireless-testing/net/mac80211/ieee80211_i.h 2009-08-20 14:53:58.000000000 +0200
@@ -1078,6 +1078,7 @@ void ieee80211_process_measurement_req(s

/* Suspend/resume and hw reconfiguration */
int ieee80211_reconfig(struct ieee80211_local *local);
+void ieee80211_stop_device(struct ieee80211_local *local);

#ifdef CONFIG_PM
int __ieee80211_suspend(struct ieee80211_hw *hw);
--- wireless-testing.orig/net/mac80211/util.c 2009-08-20 14:52:09.000000000 +0200
+++ wireless-testing/net/mac80211/util.c 2009-08-20 14:55:43.000000000 +0200
@@ -1007,6 +1007,16 @@ u32 ieee80211_sta_get_rates(struct ieee8
return supp_rates;
}

+void ieee80211_stop_device(struct ieee80211_local *local)
+{
+ ieee80211_led_radio(local, false);
+
+ cancel_work_sync(&local->reconfig_filter);
+ drv_stop(local);
+
+ flush_workqueue(local->workqueue);
+}
+
int ieee80211_reconfig(struct ieee80211_local *local)
{
struct ieee80211_hw *hw = &local->hw;
--- wireless-testing.orig/net/mac80211/pm.c 2009-08-20 14:55:52.000000000 +0200
+++ wireless-testing/net/mac80211/pm.c 2009-08-20 14:56:28.000000000 +0200
@@ -107,17 +107,8 @@ int __ieee80211_suspend(struct ieee80211
}

/* stop hardware - this must stop RX */
- if (local->open_count) {
- ieee80211_led_radio(local, false);
+ if (local->open_count)
ieee80211_stop_device(local);
- }
-
- /*
- * flush again, in case driver queued work -- it
- * shouldn't be doing (or cancel everything in the
- * stop callback) that but better safe than sorry.
- */
- flush_workqueue(local->workqueue);

local->suspended = true;
/* need suspended to be visible before quiescing is false */




2009-08-20 18:02:22

by Johannes Berg

[permalink] [raw]
Subject: [PATCH v2] mac80211: fix configure_filter invocation after stop

Since configure_filter can sleep now, any multicast
configuration needed to be postponed to a work struct.
This, however, lead to a problem that we could queue
the work, stop the device and then afterwards invoke
configure_filter which may lead to driver hangs and is
a bug. To fix this, we can just cancel the filter work
since it's unnecessary to do after stopping the hw.

Since there are various places that call drv_stop, and
two of them do very similar things, the code for them
can be put into a shared function at the same time.

Signed-off-by: Johannes Berg <[email protected]>
Reported-by: Lennert Buytenhek <[email protected]>
---
messed up with quilt in v1

net/mac80211/ieee80211_i.h | 1 +
net/mac80211/iface.c | 6 +-----
net/mac80211/pm.c | 13 ++-----------
net/mac80211/util.c | 10 ++++++++++
4 files changed, 14 insertions(+), 16 deletions(-)

--- wireless-testing.orig/net/mac80211/pm.c 2009-08-20 20:01:01.000000000 +0200
+++ wireless-testing/net/mac80211/pm.c 2009-08-20 20:01:14.000000000 +0200
@@ -107,17 +107,8 @@ int __ieee80211_suspend(struct ieee80211
}

/* stop hardware - this must stop RX */
- if (local->open_count) {
- ieee80211_led_radio(local, false);
- drv_stop(local);
- }
-
- /*
- * flush again, in case driver queued work -- it
- * shouldn't be doing (or cancel everything in the
- * stop callback) that but better safe than sorry.
- */
- flush_workqueue(local->workqueue);
+ if (local->open_count)
+ ieee80211_stop_device(local);

local->suspended = true;
/* need suspended to be visible before quiescing is false */
--- wireless-testing.orig/net/mac80211/iface.c 2009-08-20 20:00:35.000000000 +0200
+++ wireless-testing/net/mac80211/iface.c 2009-08-20 20:01:14.000000000 +0200
@@ -552,11 +552,7 @@ static int ieee80211_stop(struct net_dev
ieee80211_recalc_ps(local, -1);

if (local->open_count == 0) {
- drv_stop(local);
-
- ieee80211_led_radio(local, false);
-
- flush_workqueue(local->workqueue);
+ ieee80211_stop_device(local);

tasklet_disable(&local->tx_pending_tasklet);
tasklet_disable(&local->tasklet);
--- wireless-testing.orig/net/mac80211/ieee80211_i.h 2009-08-20 20:00:35.000000000 +0200
+++ wireless-testing/net/mac80211/ieee80211_i.h 2009-08-20 20:01:14.000000000 +0200
@@ -1078,6 +1078,7 @@ void ieee80211_process_measurement_req(s

/* Suspend/resume and hw reconfiguration */
int ieee80211_reconfig(struct ieee80211_local *local);
+void ieee80211_stop_device(struct ieee80211_local *local);

#ifdef CONFIG_PM
int __ieee80211_suspend(struct ieee80211_hw *hw);
--- wireless-testing.orig/net/mac80211/util.c 2009-08-20 20:00:35.000000000 +0200
+++ wireless-testing/net/mac80211/util.c 2009-08-20 20:01:14.000000000 +0200
@@ -1007,6 +1007,16 @@ u32 ieee80211_sta_get_rates(struct ieee8
return supp_rates;
}

+void ieee80211_stop_device(struct ieee80211_local *local)
+{
+ ieee80211_led_radio(local, false);
+
+ cancel_work_sync(&local->reconfig_filter);
+ drv_stop(local);
+
+ flush_workqueue(local->workqueue);
+}
+
int ieee80211_reconfig(struct ieee80211_local *local)
{
struct ieee80211_hw *hw = &local->hw;



2009-08-20 19:56:11

by Lennert Buytenhek

[permalink] [raw]
Subject: Re: [PATCH v2] mac80211: fix configure_filter invocation after stop

On Thu, Aug 20, 2009 at 08:02:20PM +0200, Johannes Berg wrote:

> Since configure_filter can sleep now, any multicast
> configuration needed to be postponed to a work struct.
> This, however, lead to a problem that we could queue
> the work, stop the device and then afterwards invoke
> configure_filter which may lead to driver hangs and is
> a bug. To fix this, we can just cancel the filter work
> since it's unnecessary to do after stopping the hw.
>
> Since there are various places that call drv_stop, and
> two of them do very similar things, the code for them
> can be put into a shared function at the same time.
>
> Signed-off-by: Johannes Berg <[email protected]>
> Reported-by: Lennert Buytenhek <[email protected]>

Seems to work for me, I now no longer see firmware commands being
posted after ->stop() is called.

Tested-by: Lennert Buytenhek <[email protected]>