hostap: Protect against initialization interrupt

Use an irq spinlock to hold off the IRQ handler until
enough early card init is complete such that the handler
can run without faulting.

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Cc: stable@kernel.org
Signed-off-by: John W. Linville <linville@tuxdriver.com>

3 files changed, 27 insertions, 3 deletions

diff --git a/drivers/net/wireless/hostap/hostap_cs.c b/drivers/net/wireless/hostap/hostap_cs.c
index db72461c486..29b31a694b5 100644
--- a/drivers/net/wireless/hostap/hostap_cs.c
+++ b/drivers/net/wireless/hostap/hostap_cs.c
@@ -594,6 +594,7 @@ static int prism2_config(struct pcmcia_device *link)
         local_info_t *local;
         int ret = 1;
         struct hostap_cs_priv *hw_priv;
+        unsigned long flags;
 
         PDEBUG(DEBUG_FLOW, "prism2_config()\n");
 
@@ -625,9 +626,15 @@ static int prism2_config(struct pcmcia_device *link)
         local->hw_priv = hw_priv;
         hw_priv->link = link;
 
+        /*
+         * Make sure the IRQ handler cannot proceed until at least
+         * dev->base_addr is initialized.
+         */
+        spin_lock_irqsave(&local->irq_init_lock, flags);
+
         ret = pcmcia_request_irq(link, prism2_interrupt);
         if (ret)
-                goto failed;
+                goto failed_unlock;
 
         /*
          * This actually configures the PCMCIA socket -- setting up
@@ -636,11 +643,13 @@ static int prism2_config(struct pcmcia_device *link)
          */
         ret = pcmcia_request_configuration(link, &link->conf);
         if (ret)
-                goto failed;
+                goto failed_unlock;
 
         dev->irq = link->irq;
         dev->base_addr = link->io.BasePort1;
 
+        spin_unlock_irqrestore(&local->irq_init_lock, flags);
+
         /* Finally, report what we've done */
         printk(KERN_INFO "%s: index 0x%02x: ",
                dev_info, link->conf.ConfigIndex);
@@ -667,6 +676,8 @@ static int prism2_config(struct pcmcia_device *link)
 
         return ret;
 
+ failed_unlock:
+         spin_unlock_irqrestore(&local->irq_init_lock, flags);
  failed:
         kfree(hw_priv);
         prism2_release((u_long)link);
diff --git a/drivers/net/wireless/hostap/hostap_hw.c b/drivers/net/wireless/hostap/hostap_hw.c
index ff9b5c88218..2f999fc94f6 100644
--- a/drivers/net/wireless/hostap/hostap_hw.c
+++ b/drivers/net/wireless/hostap/hostap_hw.c
@@ -2621,6 +2621,18 @@ static irqreturn_t prism2_interrupt(int irq, void *dev_id)
         iface = netdev_priv(dev);
         local = iface->local;
 
+        /* Detect early interrupt before driver is fully configued */
+        spin_lock(&local->irq_init_lock);
+        if (!dev->base_addr) {
+                if (net_ratelimit()) {
+                        printk(KERN_DEBUG "%s: Interrupt, but dev not configured\n",
+                               dev->name);
+                }
+                spin_unlock(&local->irq_init_lock);
+                return IRQ_HANDLED;
+        }
+        spin_unlock(&local->irq_init_lock);
+
         prism2_io_debug_add(dev, PRISM2_IO_DEBUG_CMD_INTERRUPT, 0, 0);
 
         if (local->func->card_present && !local->func->card_present(local)) {
@@ -3138,6 +3150,7 @@ prism2_init_local_data(struct prism2_helper_functions *funcs, int card_idx,
         spin_lock_init(&local->cmdlock);
         spin_lock_init(&local->baplock);
         spin_lock_init(&local->lock);
+        spin_lock_init(&local->irq_init_lock);
         mutex_init(&local->rid_bap_mtx);
 
         if (card_idx < 0 || card_idx >= MAX_PARM_DEVICES)
diff --git a/drivers/net/wireless/hostap/hostap_wlan.h b/drivers/net/wireless/hostap/hostap_wlan.h
index 3d238917af0..1ba33be98b2 100644
--- a/drivers/net/wireless/hostap/hostap_wlan.h
+++ b/drivers/net/wireless/hostap/hostap_wlan.h
@@ -654,7 +654,7 @@ struct local_info {
         rwlock_t iface_lock; /* hostap_interfaces read lock; use write lock
                               * when removing entries from the list.
                               * TX and RX paths can use read lock. */
-        spinlock_t cmdlock, baplock, lock;
+        spinlock_t cmdlock, baplock, lock, irq_init_lock;
         struct mutex rid_bap_mtx;
         u16 infofid; /* MAC buffer id for info frame */
         /* txfid, intransmitfid, next_txtid, and next_alloc are protected by