hostap: Protect against initialization interrupt

commit d6a574ff6bfb842bdb98065da053881ff527be46 upstream.

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>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 24 insertions, 1 deletions

diff --git a/drivers/net/wireless/hostap/hostap_cs.c b/drivers/net/wireless/hostap/hostap_cs.c
index 3b4e55cf33cd..055e9914db81 100644
--- a/drivers/net/wireless/hostap/hostap_cs.c
+++ b/drivers/net/wireless/hostap/hostap_cs.c
@@ -557,6 +557,7 @@ static int prism2_config(struct pcmcia_device *link)
 	config_info_t conf;
 	cistpl_cftable_entry_t dflt = { 0 };
 	struct hostap_cs_priv *hw_priv;
+	unsigned long flags;
 
 	PDEBUG(DEBUG_FLOW, "prism2_config()\n");
 
@@ -688,6 +689,12 @@ static int prism2_config(struct pcmcia_device *link)
 	link->dev_node = &hw_priv->node;
 
 	/*
+	 * Make sure the IRQ handler cannot proceed until at least
+	 * dev->base_addr is initialized.
+	 */
+	spin_lock_irqsave(&local->irq_init_lock, flags);
+
+	/*
 	 * Allocate an interrupt line.  Note that this does not assign a
 	 * handler to the interrupt, unless the 'Handler' member of the
 	 * irq structure is initialized.
@@ -712,6 +719,8 @@ static int prism2_config(struct pcmcia_device *link)
 	dev->irq = link->irq.AssignedIRQ;
 	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);
@@ -742,6 +751,7 @@ static int prism2_config(struct pcmcia_device *link)
 	return ret;
 
  cs_failed:
+	spin_unlock_irqrestore(&local->irq_init_lock, flags);
 	cs_error(link, last_fn, last_ret);
 
  failed:
diff --git a/drivers/net/wireless/hostap/hostap_hw.c b/drivers/net/wireless/hostap/hostap_hw.c
index 3153fe9d7ce0..04b890f42026 100644
--- a/drivers/net/wireless/hostap/hostap_hw.c
+++ b/drivers/net/wireless/hostap/hostap_hw.c
@@ -2631,6 +2631,18 @@ 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)) {
@@ -3187,6 +3199,7 @@ 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 a68f97c39359..1c986f2923ca 100644
--- a/drivers/net/wireless/hostap/hostap_wlan.h
+++ b/drivers/net/wireless/hostap/hostap_wlan.h
@@ -653,7 +653,7 @@ 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