Merge tag 'v3.12-rc5' into stable/for-linus-3.13

Linux 3.12-rc5

Because the Stefano branch (for SWIOTLB ARM changes) is based on that.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

* tag 'v3.12-rc5': (550 commits)
  Linux 3.12-rc5
  watchdog: sunxi: Fix section mismatch
  watchdog: kempld_wdt: Fix bit mask definition
  watchdog: ts72xx_wdt: locking bug in ioctl
  ARM: exynos: dts: Update 5250 arch timer node with clock frequency
  parisc: let probe_kernel_read() capture access to page zero
  parisc: optimize variable initialization in do_page_fault
  parisc: fix interruption handler to respect pagefault_disable()
  parisc: mark parisc_terminate() noreturn and cold.
  parisc: remove unused syscall_ipi() function.
  parisc: kill SMP single function call interrupt
  parisc: Export flush_cache_page() (needed by lustre)
  vfs: allow O_PATH file descriptors for fstatfs()
  ext4: fix memory leak in xattr
  ARC: Ignore ptrace SETREGSET request for synthetic register "stop_pc"
  ALSA: hda - Sony VAIO Pro 13 (haswell) now has a working headset jack
  ALSA: hda - Add a headset mic model for ALC269 and friends
  ALSA: hda - Fix microphone for Sony VAIO Pro 13 (Haswell model)
  compiler/gcc4: Add quirk for 'asm goto' miscompilation bug
  Revert "i915: Update VGA arbiter support for newer devices"
  ...

1 files changed, 48 insertions, 1 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 5c713f2239c..65f829cfd92 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5247,10 +5247,12 @@ static int dev_new_index(struct net *net)
 
 /* Delayed registration/unregisteration */
 static LIST_HEAD(net_todo_list);
+static DECLARE_WAIT_QUEUE_HEAD(netdev_unregistering_wq);
 
 static void net_set_todo(struct net_device *dev)
 {
 	list_add_tail(&dev->todo_list, &net_todo_list);
+	dev_net(dev)->dev_unreg_count++;
 }
 
 static void rollback_registered_many(struct list_head *head)
@@ -5918,6 +5920,12 @@ void netdev_run_todo(void)
 		if (dev->destructor)
 			dev->destructor(dev);
 
+		/* Report a network device has been unregistered */
+		rtnl_lock();
+		dev_net(dev)->dev_unreg_count--;
+		__rtnl_unlock();
+		wake_up(&netdev_unregistering_wq);
+
 		/* Free network device */
 		kobject_put(&dev->dev.kobj);
 	}
@@ -6603,6 +6611,34 @@ static void __net_exit default_device_exit(struct net *net)
 	rtnl_unlock();
 }
 
+static void __net_exit rtnl_lock_unregistering(struct list_head *net_list)
+{
+	/* Return with the rtnl_lock held when there are no network
+	 * devices unregistering in any network namespace in net_list.
+	 */
+	struct net *net;
+	bool unregistering;
+	DEFINE_WAIT(wait);
+
+	for (;;) {
+		prepare_to_wait(&netdev_unregistering_wq, &wait,
+				TASK_UNINTERRUPTIBLE);
+		unregistering = false;
+		rtnl_lock();
+		list_for_each_entry(net, net_list, exit_list) {
+			if (net->dev_unreg_count > 0) {
+				unregistering = true;
+				break;
+			}
+		}
+		if (!unregistering)
+			break;
+		__rtnl_unlock();
+		schedule();
+	}
+	finish_wait(&netdev_unregistering_wq, &wait);
+}
+
 static void __net_exit default_device_exit_batch(struct list_head *net_list)
 {
 	/* At exit all network devices most be removed from a network
@@ -6614,7 +6650,18 @@ static void __net_exit default_device_exit_batch(struct list_head *net_list)
 	struct net *net;
 	LIST_HEAD(dev_kill_list);
 
-	rtnl_lock();
+	/* To prevent network device cleanup code from dereferencing
+	 * loopback devices or network devices that have been freed
+	 * wait here for all pending unregistrations to complete,
+	 * before unregistring the loopback device and allowing the
+	 * network namespace be freed.
+	 *
+	 * The netdev todo list containing all network devices
+	 * unregistrations that happen in default_device_exit_batch
+	 * will run in the rtnl_unlock() at the end of
+	 * default_device_exit_batch.
+	 */
+	rtnl_lock_unregistering(net_list);
 	list_for_each_entry(net, net_list, exit_list) {
 		for_each_netdev_reverse(net, dev) {
 			if (dev->rtnl_link_ops)