1 files changed, 9 insertions, 4 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index b9018bfa0a97..eba1271b9735 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -48,6 +48,7 @@
 #include <linux/kernel.h>
 #include <linux/major.h>
 #include <linux/slab.h>
+#include <linux/smp_lock.h>
 #include <linux/poll.h>
 #include <linux/fcntl.h>
 #include <linux/init.h>
@@ -802,22 +803,26 @@ static int tun_chr_fasync(int fd, struct file *file, int on)
 
         DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
 
+        lock_kernel();
         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
-                return ret;
+                goto out;
 
         if (on) {
                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
                 if (ret)
-                        return ret;
+                        goto out;
                 tun->flags |= TUN_FASYNC;
         } else
                 tun->flags &= ~TUN_FASYNC;
-
-        return 0;
+        ret = 0;
+out:
+        unlock_kernel();
+        return ret;
 }
 
 static int tun_chr_open(struct inode *inode, struct file * file)
 {
+        cycle_kernel_lock();
         DBG1(KERN_INFO "tunX: tun_chr_open\n");
         file->private_data = NULL;
         return 0;