[IPV6]: Fix addrconf dead lock.

We need to release idev->lcok before we call addrconf_dad_stop().
It calls ipv6_addr_del(), which will hold idev->lock.

Bug spotted by Yasuyuki KOZAKAI <yasuyuki.kozakai@toshiba.co.jp>.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 4 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 2a6439e3c91c..a60585fd85ad 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2467,11 +2467,9 @@ static void addrconf_dad_start(struct inet6_ifaddr *ifp, u32 flags)
                 return;
         }
 
-        if (idev->if_flags & IF_READY) {
-                addrconf_dad_kick(ifp);
-                spin_unlock_bh(&ifp->lock);
-        } else {
+        if (!(idev->if_flags & IF_READY)) {
                 spin_unlock_bh(&ifp->lock);
+                read_unlock_bh(&idev->lock);
                 /*
                  * If the defice is not ready:
                  * - keep it tentative if it is a permanent address.
@@ -2479,7 +2477,10 @@ static void addrconf_dad_start(struct inet6_ifaddr *ifp, u32 flags)
                  */
                 in6_ifa_hold(ifp);
                 addrconf_dad_stop(ifp);
+                return;
         }
+        addrconf_dad_kick(ifp);
+        spin_unlock_bh(&ifp->lock);
 out:
         read_unlock_bh(&idev->lock);
 }