rtnetlink: make rtnl_fill_link_ifmap() RCU ready

Use READ_ONCE() to read the following device fields:

	dev->mem_start
	dev->mem_end
	dev->base_addr
	dev->irq
	dev->dma
	dev->if_port

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 1b26dfa5668d22fb2e30ceefbf143e98df13ae29..2d83ab76a3c95c3200016a404e740bb058f23ada 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1455,17 +1455,18 @@ static noinline_for_stack int rtnl_fill_vf(struct sk_buff *skb,
        return 0;
 }
 
-static int rtnl_fill_link_ifmap(struct sk_buff *skb, struct net_device *dev)
+static int rtnl_fill_link_ifmap(struct sk_buff *skb,
+                               const struct net_device *dev)
 {
        struct rtnl_link_ifmap map;
 
        memset(&map, 0, sizeof(map));
-       map.mem_start   = dev->mem_start;
-       map.mem_end     = dev->mem_end;
-       map.base_addr   = dev->base_addr;
-       map.irq         = dev->irq;
-       map.dma         = dev->dma;
-       map.port        = dev->if_port;
+       map.mem_start = READ_ONCE(dev->mem_start);
+       map.mem_end   = READ_ONCE(dev->mem_end);
+       map.base_addr = READ_ONCE(dev->base_addr);
+       map.irq       = READ_ONCE(dev->irq);
+       map.dma       = READ_ONCE(dev->dma);
+       map.port      = READ_ONCE(dev->if_port);
 
        if (nla_put_64bit(skb, IFLA_MAP, sizeof(map), &map, IFLA_PAD))
                return -EMSGSIZE;
@@ -1875,9 +1876,6 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb,
                        goto nla_put_failure;
        }
 
-       if (rtnl_fill_link_ifmap(skb, dev))
-               goto nla_put_failure;
-
        if (dev->addr_len) {
                if (nla_put(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr) ||
                    nla_put(skb, IFLA_BROADCAST, dev->addr_len, dev->broadcast))
@@ -1927,6 +1925,9 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb,
        rcu_read_lock();
        if (rtnl_fill_link_af(skb, dev, ext_filter_mask))
                goto nla_put_failure_rcu;
+       if (rtnl_fill_link_ifmap(skb, dev))
+               goto nla_put_failure_rcu;
+
        rcu_read_unlock();
 
        if (rtnl_fill_prop_list(skb, dev))