iwlwifi: fix race condition during driver unload

This patch fixed the OOPS when load the driver while rf-kill is on then
unload the driver right after load. a race condition caused the interupt
handler to schedule the tasklet which will run right after the driver pci_remove
causing invalid poiter OOPS.

Signed-off-by: Mohamed Abbas <mabbas@linux.intel.com>
Signed-off-by: Joonwoo Park <joonwpark81@gmail.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c b/drivers/net/wireless/iwlwifi/iwl3945-base.c
index ab635dc..2a5245b 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl3945-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c
@@ -4153,6 +4153,16 @@ static void iwl3945_enable_interrupts(struct iwl3945_priv *priv)
        iwl3945_write32(priv, CSR_INT_MASK, CSR_INI_SET_MASK);
 }
 
+
+/* call this function to flush any scheduled tasklet */
+static inline void iwl_synchronize_irq(struct iwl3945_priv *priv)
+{
+       /* wait to make sure we flush pedding tasklet*/
+       synchronize_irq(priv->pci_dev->irq);
+       tasklet_kill(&priv->irq_tasklet);
+}
+
+
 static inline void iwl3945_disable_interrupts(struct iwl3945_priv *priv)
 {
        clear_bit(STATUS_INT_ENABLED, &priv->status);
@@ -4552,7 +4562,9 @@ static void iwl3945_irq_tasklet(struct iwl3945_priv *priv)
        }
 
        /* Re-enable all interrupts */
-       iwl3945_enable_interrupts(priv);
+       /* only Re-enable if disabled by irq */
+       if (test_bit(STATUS_INT_ENABLED, &priv->status))
+               iwl3945_enable_interrupts(priv);
 
 #ifdef CONFIG_IWL3945_DEBUG
        if (iwl3945_debug_level & (IWL_DL_ISR)) {
@@ -4616,7 +4628,9 @@ unplugged:
 
  none:
        /* re-enable interrupts here since we don't have anything to service. */
-       iwl3945_enable_interrupts(priv);
+       /* only Re-enable if disabled by irq */
+       if (test_bit(STATUS_INT_ENABLED, &priv->status))
+               iwl3945_enable_interrupts(priv);
        spin_unlock(&priv->lock);
        return IRQ_NONE;
 }
@@ -5905,7 +5919,10 @@ static void __iwl3945_down(struct iwl3945_priv *priv)
        iwl3945_write32(priv, CSR_RESET, CSR_RESET_REG_FLAG_NEVO_RESET);
 
        /* tell the device to stop sending interrupts */
+       spin_lock_irqsave(&priv->lock, flags);
        iwl3945_disable_interrupts(priv);
+       spin_unlock_irqrestore(&priv->lock, flags);
+       iwl_synchronize_irq(priv);
 
        if (priv->mac80211_registered)
                ieee80211_stop_queues(priv->hw);
@@ -7943,6 +7960,7 @@ static int iwl3945_pci_probe(struct pci_dev *pdev, const struct pci_device_id *e
        struct ieee80211_hw *hw;
        struct iwl_3945_cfg *cfg = (struct iwl_3945_cfg *)(ent->driver_data);
        int i;
+       unsigned long flags;
        DECLARE_MAC_BUF(mac);
 
        /* Disabling hardware scan means that mac80211 will perform scans
@@ -8093,7 +8111,9 @@ static int iwl3945_pci_probe(struct pci_dev *pdev, const struct pci_device_id *e
        priv->power_mode = IWL_POWER_AC;
        priv->user_txpower_limit = IWL_DEFAULT_TX_POWER;
 
+       spin_lock_irqsave(&priv->lock, flags);
        iwl3945_disable_interrupts(priv);
+       spin_unlock_irqrestore(&priv->lock, flags);
 
        err = sysfs_create_group(&pdev->dev.kobj, &iwl3945_attribute_group);
        if (err) {
@@ -8180,6 +8200,7 @@ static void __devexit iwl3945_pci_remove(struct pci_dev *pdev)
        struct iwl3945_priv *priv = pci_get_drvdata(pdev);
        struct list_head *p, *q;
        int i;
+       unsigned long flags;
 
        if (!priv)
                return;
@@ -8190,6 +8211,15 @@ static void __devexit iwl3945_pci_remove(struct pci_dev *pdev)
 
        iwl3945_down(priv);
 
+       /* make sure we flush any pending irq or
+        * tasklet for the driver
+        */
+       spin_lock_irqsave(&priv->lock, flags);
+       iwl3945_disable_interrupts(priv);
+       spin_unlock_irqrestore(&priv->lock, flags);
+
+       iwl_synchronize_irq(priv);
+
        /* Free MAC hash list for ADHOC */
        for (i = 0; i < IWL_IBSS_MAC_HASH_SIZE; i++) {
                list_for_each_safe(p, q, &priv->ibss_mac_hash[i]) {

diff --git a/drivers/net/wireless/iwlwifi/iwl4965-base.c b/drivers/net/wireless/iwlwifi/iwl4965-base.c
index 7f56565..29e8431 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl4965-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl4965-base.c
@@ -4285,6 +4285,14 @@ static void iwl4965_enable_interrupts(struct iwl_priv *priv)
        iwl_write32(priv, CSR_INT_MASK, CSR_INI_SET_MASK);
 }
 
+/* call this function to flush any scheduled tasklet */
+static inline void iwl_synchronize_irq(struct iwl_priv *priv)
+{
+       /* wait to make sure we flush pedding tasklet*/
+       synchronize_irq(priv->pci_dev->irq);
+       tasklet_kill(&priv->irq_tasklet);
+}
+
 static inline void iwl4965_disable_interrupts(struct iwl_priv *priv)
 {
        clear_bit(STATUS_INT_ENABLED, &priv->status);
@@ -4668,7 +4676,9 @@ static void iwl4965_irq_tasklet(struct iwl_priv *priv)
        }
 
        /* Re-enable all interrupts */
-       iwl4965_enable_interrupts(priv);
+       /* only Re-enable if diabled by irq */
+       if (test_bit(STATUS_INT_ENABLED, &priv->status))
+               iwl4965_enable_interrupts(priv);
 
 #ifdef CONFIG_IWLWIFI_DEBUG
        if (iwl_debug_level & (IWL_DL_ISR)) {
@@ -4733,7 +4743,9 @@ static irqreturn_t iwl4965_isr(int irq, void *data)
 
  none:
        /* re-enable interrupts here since we don't have anything to service. */
-       iwl4965_enable_interrupts(priv);
+       /* only Re-enable if diabled by irq */
+       if (test_bit(STATUS_INT_ENABLED, &priv->status))
+               iwl4965_enable_interrupts(priv);
        spin_unlock(&priv->lock);
        return IRQ_NONE;
 }
@@ -5772,7 +5784,10 @@ static void __iwl4965_down(struct iwl_priv *priv)
        iwl_write32(priv, CSR_RESET, CSR_RESET_REG_FLAG_NEVO_RESET);
 
        /* tell the device to stop sending interrupts */
+       spin_lock_irqsave(&priv->lock, flags);
        iwl4965_disable_interrupts(priv);
+       spin_unlock_irqrestore(&priv->lock, flags);
+       iwl_synchronize_irq(priv);
 
        if (priv->mac80211_registered)
                ieee80211_stop_queues(priv->hw);
@@ -7996,6 +8011,7 @@ static int iwl4965_pci_probe(struct pci_dev *pdev, const struct pci_device_id *e
        struct iwl_priv *priv;
        struct ieee80211_hw *hw;
        struct iwl_cfg *cfg = (struct iwl_cfg *)(ent->driver_data);
+       unsigned long flags;
        DECLARE_MAC_BUF(mac);
 
        /************************
@@ -8133,7 +8149,9 @@ static int iwl4965_pci_probe(struct pci_dev *pdev, const struct pci_device_id *e
        /********************
         * 8. Setup services
         ********************/
+       spin_lock_irqsave(&priv->lock, flags);
        iwl4965_disable_interrupts(priv);
+       spin_unlock_irqrestore(&priv->lock, flags);
 
        err = sysfs_create_group(&pdev->dev.kobj, &iwl4965_attribute_group);
        if (err) {
@@ -8182,6 +8200,7 @@ static void __devexit iwl4965_pci_remove(struct pci_dev *pdev)
        struct iwl_priv *priv = pci_get_drvdata(pdev);
        struct list_head *p, *q;
        int i;
+       unsigned long flags;
 
        if (!priv)
                return;
@@ -8192,6 +8211,15 @@ static void __devexit iwl4965_pci_remove(struct pci_dev *pdev)
 
        iwl4965_down(priv);
 
+       /* make sure we flush any pending irq or
+        * tasklet for the driver
+        */
+       spin_lock_irqsave(&priv->lock, flags);
+       iwl4965_disable_interrupts(priv);
+       spin_unlock_irqrestore(&priv->lock, flags);
+
+       iwl_synchronize_irq(priv);
+
        /* Free MAC hash list for ADHOC */
        for (i = 0; i < IWL_IBSS_MAC_HASH_SIZE; i++) {
                list_for_each_safe(p, q, &priv->ibss_mac_hash[i]) {