[patch 009/100] rt2x00: Fix SLAB corruption during rmmod

Chris Wright
2009-04-23T07:32:43Z

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-stable review patch. If anyone has any objections, please let us know.
---------------------

From: Gertjan van Wingerde <gwingerde@gmail.com>

At rmmod stage, the code path is the following one :

rt2x00lib_remove_dev
->  rt2x00lib_uninitialize()
-> rt2x00rfkill_unregister()
-> rfkill_unregister()
-> rt2x00rfkill_free()
-> rfkill_free()

The problem is that rfkill_free should not be called after rfkill_register
otherwise put_device(&rfkill->dev) will be called 2 times. This patch
fixes this by only calling rt2x00rfkill_free() when rt2x00rfkill_register()
hasn't been called or has failed.

This patch is for 2.6.29 only. The code in question has completely disappeared
in 2.6.30 and does not contain this bug.

Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Tested-by: Arnaud Patard <apatard@mandriva.com>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---
drivers/net/wireless/rt2x00/rt2x00.h | 3 -
drivers/net/wireless/rt2x00/rt2x00dev.c | 2
drivers/net/wireless/rt2x00/rt2x00lib.h | 10 ---
drivers/net/wireless/rt2x00/rt2x00rfkill.c | 86 +++++++++++++----------------
4 files changed, 40 insertions(+), 61 deletions(-)

--- a/drivers/net/wireless/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/rt2x00/rt2x00.h
@@ -687,8 +687,7 @@ struct rt2x00_dev {
*/
#ifdef CONFIG_RT2X00_LIB_RFKILL
unsigned long rfkill_state;
-#define RFKILL_STATE_ALLOCATED 1
-#define RFKILL_STATE_REGISTERED 2
+#define RFKILL_STATE_REGISTERED 1
struct rfkill *rfkill;
struct delayed_work rfkill_work;
#endif /* CONFIG_RT2X00_LIB_RFKILL */
--- a/drivers/net/wireless/rt2x00/rt2x00dev.c
+++ b/drivers/net/wireless/rt2x00/rt2x00dev.c
@@ -1105,7 +1105,6 @@ int rt2x00lib_probe_dev(struct rt2x00_de
* Register extra components.
*/
rt2x00leds_register(rt2x00dev);
- rt2x00rfkill_allocate(rt2x00dev);
rt2x00debug_register(rt2x00dev);

set_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags);
@@ -1137,7 +1136,6 @@ void rt2x00lib_remove_dev(struct rt2x00_
* Free extra components
*/
rt2x00debug_deregister(rt2x00dev);
- rt2x00rfkill_free(rt2x00dev);
rt2x00leds_unregister(rt2x00dev);

/*
--- a/drivers/net/wireless/rt2x00/rt2x00lib.h
+++ b/drivers/net/wireless/rt2x00/rt2x00lib.h
@@ -260,8 +260,6 @@ static inline void rt2x00crypto_rx_inser
#ifdef CONFIG_RT2X00_LIB_RFKILL
void rt2x00rfkill_register(struct rt2x00_dev *rt2x00dev);
void rt2x00rfkill_unregister(struct rt2x00_dev *rt2x00dev);
-void rt2x00rfkill_allocate(struct rt2x00_dev *rt2x00dev);
-void rt2x00rfkill_free(struct rt2x00_dev *rt2x00dev);
#else
static inline void rt2x00rfkill_register(struct rt2x00_dev *rt2x00dev)
{
@@ -270,14 +268,6 @@ static inline void rt2x00rfkill_register
static inline void rt2x00rfkill_unregister(struct rt2x00_dev *rt2x00dev)
{
}
-
-static inline void rt2x00rfkill_allocate(struct rt2x00_dev *rt2x00dev)
-{
-}
-
-static inline void rt2x00rfkill_free(struct rt2x00_dev *rt2x00dev)
-{
-}
#endif /* CONFIG_RT2X00_LIB_RFKILL */

/*
--- a/drivers/net/wireless/rt2x00/rt2x00rfkill.c
+++ b/drivers/net/wireless/rt2x00/rt2x00rfkill.c
@@ -94,14 +94,50 @@ static void rt2x00rfkill_poll(struct wor
&rt2x00dev->rfkill_work, RFKILL_POLL_INTERVAL);
}

+static int rt2x00rfkill_allocate(struct rt2x00_dev *rt2x00dev)
+{
+ struct device *dev = wiphy_dev(rt2x00dev->hw->wiphy);
+
+ rt2x00dev->rfkill = rfkill_allocate(dev, RFKILL_TYPE_WLAN);
+ if (!rt2x00dev->rfkill)
+ return -ENOMEM;
+
+ rt2x00dev->rfkill->name = rt2x00dev->ops->name;
+ rt2x00dev->rfkill->data = rt2x00dev;
+ rt2x00dev->rfkill->toggle_radio = rt2x00rfkill_toggle_radio;
+ if (test_bit(CONFIG_SUPPORT_HW_BUTTON, &rt2x00dev->flags)) {
+ rt2x00dev->rfkill->get_state = rt2x00rfkill_get_state;
+ rt2x00dev->rfkill->state =
+ rt2x00dev->ops->lib->rfkill_poll(rt2x00dev) ?
+ RFKILL_STATE_SOFT_BLOCKED : RFKILL_STATE_UNBLOCKED;
+ } else {
+ rt2x00dev->rfkill->state = RFKILL_STATE_UNBLOCKED;
+ }
+
+ INIT_DELAYED_WORK(&rt2x00dev->rfkill_work, rt2x00rfkill_poll);
+
+ return 0;
+}
+
+static void rt2x00rfkill_free(struct rt2x00_dev *rt2x00dev)
+{
+ rfkill_free(rt2x00dev->rfkill);
+ rt2x00dev->rfkill = NULL;
+}
+
void rt2x00rfkill_register(struct rt2x00_dev *rt2x00dev)
{
- if (!test_bit(RFKILL_STATE_ALLOCATED, &rt2x00dev->rfkill_state) ||
- test_bit(RFKILL_STATE_REGISTERED, &rt2x00dev->rfkill_state))
+ if (test_bit(RFKILL_STATE_REGISTERED, &rt2x00dev->rfkill_state))
+ return;
+
+ if (rt2x00rfkill_allocate(rt2x00dev)) {
+ ERROR(rt2x00dev, "Failed to allocate rfkill handler.\n");
return;
+ }

if (rfkill_register(rt2x00dev->rfkill)) {
ERROR(rt2x00dev, "Failed to register rfkill handler.\n");
+ rt2x00rfkill_free(rt2x00dev);
return;
}

@@ -117,8 +153,7 @@ void rt2x00rfkill_register(struct rt2x00

void rt2x00rfkill_unregister(struct rt2x00_dev *rt2x00dev)
{
- if (!test_bit(RFKILL_STATE_ALLOCATED, &rt2x00dev->rfkill_state) ||
- !test_bit(RFKILL_STATE_REGISTERED, &rt2x00dev->rfkill_state))
+ if (!test_bit(RFKILL_STATE_REGISTERED, &rt2x00dev->rfkill_state))
return;

cancel_delayed_work_sync(&rt2x00dev->rfkill_work);
@@ -127,46 +162,3 @@ void rt2x00rfkill_unregister(struct rt2x

__clear_bit(RFKILL_STATE_REGISTERED, &rt2x00dev->rfkill_state);
}
-
-void rt2x00rfkill_allocate(struct rt2x00_dev *rt2x00dev)
-{
- struct device *dev = wiphy_dev(rt2x00dev->hw->wiphy);
-
- if (test_bit(RFKILL_STATE_ALLOCATED, &rt2x00dev->rfkill_state))
- return;
-
- rt2x00dev->rfkill = rfkill_allocate(dev, RFKILL_TYPE_WLAN);
- if (!rt2x00dev->rfkill) {
- ERROR(rt2x00dev, "Failed to allocate rfkill handler.\n");
- return;
- }
-
- __set_bit(RFKILL_STATE_ALLOCATED, &rt2x00dev->rfkill_state);
-
- rt2x00dev->rfkill->name = rt2x00dev->ops->name;
- rt2x00dev->rfkill->data = rt2x00dev;
- rt2x00dev->rfkill->toggle_radio = rt2x00rfkill_toggle_radio;
- if (test_bit(CONFIG_SUPPORT_HW_BUTTON, &rt2x00dev->flags)) {
- rt2x00dev->rfkill->get_state = rt2x00rfkill_get_state;
- rt2x00dev->rfkill->state =
- rt2x00dev->ops->lib->rfkill_poll(rt2x00dev) ?
- RFKILL_STATE_SOFT_BLOCKED : RFKILL_STATE_UNBLOCKED;
- } else {
- rt2x00dev->rfkill->state = RFKILL_STATE_UNBLOCKED;
- }
-
- INIT_DELAYED_WORK(&rt2x00dev->rfkill_work, rt2x00rfkill_poll);
-
- return;
-}
-
-void rt2x00rfkill_free(struct rt2x00_dev *rt2x00dev)
-{
- if (!test_bit(RFKILL_STATE_ALLOCATED, &rt2x00dev->rfkill_state))
- return;
-
- cancel_delayed_work_sync(&rt2x00dev->rfkill_work);
-
- rfkill_free(rt2x00dev->rfkill);
- rt2x00dev->rfkill = NULL;
-}