1 files changed, 19 insertions, 2 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 7304ea8a1f13..2a5f55866429 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -203,6 +203,8 @@ static struct list_head offload_base __read_mostly;
 DEFINE_RWLOCK(dev_base_lock);
 EXPORT_SYMBOL(dev_base_lock);
 
+DEFINE_SEQLOCK(devnet_rename_seq);
+
 static inline void dev_base_seq_inc(struct net *net)
 {
         while (++net->dev_base_seq == 0);
@@ -1091,22 +1093,31 @@ int dev_change_name(struct net_device *dev, const char *newname)
         if (dev->flags & IFF_UP)
                 return -EBUSY;
 
-        if (strncmp(newname, dev->name, IFNAMSIZ) == 0)
+        write_seqlock(&devnet_rename_seq);
+
+        if (strncmp(newname, dev->name, IFNAMSIZ) == 0) {
+                write_sequnlock(&devnet_rename_seq);
                 return 0;
+        }
 
         memcpy(oldname, dev->name, IFNAMSIZ);
 
         err = dev_get_valid_name(net, dev, newname);
-        if (err < 0)
+        if (err < 0) {
+                write_sequnlock(&devnet_rename_seq);
                 return err;
+        }
 
 rollback:
         ret = device_rename(&dev->dev, dev->name);
         if (ret) {
                 memcpy(dev->name, oldname, IFNAMSIZ);
+                write_sequnlock(&devnet_rename_seq);
                 return ret;
         }
 
+        write_sequnlock(&devnet_rename_seq);
+
         write_lock_bh(&dev_base_lock);
         hlist_del_rcu(&dev->name_hlist);
         write_unlock_bh(&dev_base_lock);
@@ -1124,6 +1135,7 @@ rollback:
                 /* err >= 0 after dev_alloc_name() or stores the first errno */
                 if (err >= 0) {
                         err = ret;
+                        write_seqlock(&devnet_rename_seq);
                         memcpy(dev->name, oldname, IFNAMSIZ);
                         goto rollback;
                 } else {
@@ -4148,6 +4160,7 @@ static int dev_ifname(struct net *net, struct ifreq __user *arg)
 {
         struct net_device *dev;
         struct ifreq ifr;
+        unsigned seq;
 
         /*
          *      Fetch the caller's info block.
@@ -4156,6 +4169,8 @@ static int dev_ifname(struct net *net, struct ifreq __user *arg)
         if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
                 return -EFAULT;
 
+retry:
+        seq = read_seqbegin(&devnet_rename_seq);
         rcu_read_lock();
         dev = dev_get_by_index_rcu(net, ifr.ifr_ifindex);
         if (!dev) {
@@ -4165,6 +4180,8 @@ static int dev_ifname(struct net *net, struct ifreq __user *arg)
 
         strcpy(ifr.ifr_name, dev->name);
         rcu_read_unlock();
+        if (read_seqretry(&devnet_rename_seq, seq))
+                goto retry;
 
         if (copy_to_user(arg, &ifr, sizeof(struct ifreq)))
                 return -EFAULT;