2009-11-30 17:31:38

by Kirill Tkhai

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Subject: [PATCH]rtl8187:fixed kernel panic on module unload

From: Tkhai Kirill <[email protected]>

rtl8187: fix kernel panic on module unload (BUG in rtl8187_leds_exit())
Signed-off-by: Tkhai Kirill <[email protected]>
---
The function rtl8187_leds_exit must not return until all LED's works
in device workqueue have completed or cancelled. Otherwise, we can get
the folowing:
wq = create_singlethread_workqueue("phyX");

INIT_DELAYED_WORK(&work, work_func);
queue_delayed_work(wq, &work, HZ/20);

destroy_workqueue(wq);

=======>kernel panic
On current vanila driver code (when running on SMP systems), panic happens
almost every time. My patch for version 2.6.31 (and 2.6.31.6 too):

--- a/drivers/net/wireless/rtl818x/rtl8187_leds.c.orig 2009-11-26 22:26:45.000000000 +0300
+++ b/drivers/net/wireless/rtl818x/rtl8187_leds.c 2009-11-28 18:22:26.659785533 +0300
@@ -36,9 +36,6 @@ static void led_turn_on(struct work_stru
if (priv->mode == NL80211_IFTYPE_UNSPECIFIED)
return ;

- /* Skip if the LED is not registered. */
- if (!led->dev)
- return;
mutex_lock(&priv->conf_mutex);
switch (led->ledpin) {
case LED_PIN_GPIO0:
@@ -74,9 +71,6 @@ static void led_turn_off(struct work_str
if (priv->mode == NL80211_IFTYPE_UNSPECIFIED)
return ;

- /* Skip if the LED is not registered. */
- if (!led->dev)
- return;
mutex_lock(&priv->conf_mutex);
switch (led->ledpin) {
case LED_PIN_GPIO0:
@@ -208,12 +202,12 @@ void rtl8187_leds_exit(struct ieee80211_
{
struct rtl8187_priv *priv = dev->priv;

- /* turn the LED off before exiting */
- queue_delayed_work(dev->workqueue, &priv->led_off, 0);
- cancel_delayed_work_sync(&priv->led_off);
- cancel_delayed_work_sync(&priv->led_on);
rtl8187_unregister_led(&priv->led_rx);
rtl8187_unregister_led(&priv->led_tx);
+ cancel_delayed_work_sync(&priv->led_on);
+ /* turn the LED off before exiting */
+ queue_delayed_work(dev->workqueue, &priv->led_off, 0);
+ flush_workqueue(dev->workqueue);
}
#endif /* def CONFIG_RTL8187_LED */



2009-11-30 17:25:19

by Larry Finger

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Subject: Re: [PATCH]rtl8187:fixed kernel panic on module unload

On 11/30/2009 11:21 AM, Тхай Кирилл wrote:
> From: Tkhai Kirill <[email protected]>
>
> rtl8187: fix kernel panic on module unload (BUG in rtl8187_leds_exit())
> Signed-off-by: Tkhai Kirill <[email protected]>
> ---
> The function rtl8187_leds_exit must not return until all LED's works
> in device workqueue have completed or cancelled. Otherwise, we can get
> the folowing:
> wq = create_singlethread_workqueue("phyX");
>
> INIT_DELAYED_WORK(&work, work_func);
> queue_delayed_work(wq, &work, HZ/20);
>
> destroy_workqueue(wq);
>
> =======>kernel panic
> On current vanila driver code (when running on SMP systems), panic happens
> almost every time. My patch for version 2.6.31 (and 2.6.31.6 too):
>
> --- a/drivers/net/wireless/rtl818x/rtl8187_leds.c.orig 2009-11-26 22:26:45.000000000 +0300
> +++ b/drivers/net/wireless/rtl818x/rtl8187_leds.c 2009-11-28 18:22:26.659785533 +0300
> @@ -36,9 +36,6 @@ static void led_turn_on(struct work_stru
> if (priv->mode == NL80211_IFTYPE_UNSPECIFIED)
> return ;
>
> - /* Skip if the LED is not registered. */
> - if (!led->dev)
> - return;
> mutex_lock(&priv->conf_mutex);
> switch (led->ledpin) {
> case LED_PIN_GPIO0:
> @@ -74,9 +71,6 @@ static void led_turn_off(struct work_str
> if (priv->mode == NL80211_IFTYPE_UNSPECIFIED)
> return ;
>
> - /* Skip if the LED is not registered. */
> - if (!led->dev)
> - return;
> mutex_lock(&priv->conf_mutex);
> switch (led->ledpin) {
> case LED_PIN_GPIO0:
> @@ -208,12 +202,12 @@ void rtl8187_leds_exit(struct ieee80211_
> {
> struct rtl8187_priv *priv = dev->priv;
>
> - /* turn the LED off before exiting */
> - queue_delayed_work(dev->workqueue, &priv->led_off, 0);
> - cancel_delayed_work_sync(&priv->led_off);
> - cancel_delayed_work_sync(&priv->led_on);
> rtl8187_unregister_led(&priv->led_rx);
> rtl8187_unregister_led(&priv->led_tx);
> + cancel_delayed_work_sync(&priv->led_on);
> + /* turn the LED off before exiting */
> + queue_delayed_work(dev->workqueue, &priv->led_off, 0);
> + flush_workqueue(dev->workqueue);
> }
> #endif /* def CONFIG_RTL8187_LED */

Have you applied the fix in mainline commit
37b12dd2b07b4d7dc222a5f7f88b25cec532b2aa? It should have fixed this problem.

Larry

2009-12-01 08:31:12

by Hin-Tak Leung

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Subject: Re: [PATCH]rtl8187:fixed kernel panic on module unload

--- On Mon, 30/11/09, Larry Finger <[email protected]> wrote:

> Have you applied the fix in mainline commit
> 37b12dd2b07b4d7dc222a5f7f88b25cec532b2aa? It should have
> fixed this problem.

37b12dd2b07b4d7dc222a5f7f88b25cec532b2aa enters mainline at v2.6.32-rc7.

I suppose it is a question for John - wireless-testing only have the vX.Y.Z-rc* and the vX.Y.Z tags... it would be useful to have the vX.Y.Z.? maintenance release tags as well (it is a matter of knowing where to git pull?) to know if a change has gone into one of the maintenance releases.