From: Benjamin Poirier <bpoirier@suse.de>
Date: Thu, 10 May 2012 15:38:37 +0000 (+0000)
Subject: igb: fix rtnl race in PM resume path
X-Git-Tag: v2.6.39-400.9.0~423^2~19^2~11^2~238
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=169d2335cca74d8b93d5f23345944a07f496a4da;p=users%2Fjedix%2Flinux-maple.git

igb: fix rtnl race in PM resume path

Since the caller (PM resume code) is not the one holding rtnl, when taking the
'else' branch rtnl may be released at any moment, thereby defeating the whole
purpose of this code block.

(cherry picked from commit cfb8c3aa59302636c69890be10b2ef23a7ca83b2)
Signed-off-by: Benjamin Poirier <bpoirier@suse.de>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Joe Jin <joe.jin@oracle.com>
---

diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index b86acf45bc28..4f23ab079651 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -1106,9 +1106,12 @@ msi_only:
 		adapter->flags |= IGB_FLAG_HAS_MSI;
 out:
 	/* Notify the stack of the (possibly) reduced queue counts. */
+	rtnl_lock();
 	netif_set_real_num_tx_queues(adapter->netdev, adapter->num_tx_queues);
-	return netif_set_real_num_rx_queues(adapter->netdev,
-					    adapter->num_rx_queues);
+	err = netif_set_real_num_rx_queues(adapter->netdev,
+		adapter->num_rx_queues);
+	rtnl_unlock();
+	return err;
 }
 
 /**
@@ -6747,18 +6750,7 @@ static int igb_resume(struct device *dev)
 	pci_enable_wake(pdev, PCI_D3hot, 0);
 	pci_enable_wake(pdev, PCI_D3cold, 0);
 
-	if (!rtnl_is_locked()) {
-		/*
-		 * shut up ASSERT_RTNL() warning in
-		 * netif_set_real_num_tx/rx_queues.
-		 */
-		rtnl_lock();
-		err = igb_init_interrupt_scheme(adapter);
-		rtnl_unlock();
-	} else {
-		err = igb_init_interrupt_scheme(adapter);
-	}
-	if (err) {
+	if (igb_init_interrupt_scheme(adapter)) {
 		dev_err(&pdev->dev, "Unable to allocate memory for queues\n");
 		return -ENOMEM;
 	}