Author: bz
Date: Tue Dec  7 22:43:29 2010
New Revision: 216277
URL: http://svn.freebsd.org/changeset/base/216277

Log:
  Loosen the locking in nd6-free() again after r216022 to avoid
  a LOR and a recursed lock.
  
  Reported by:  delphij
  Tested by:    delphij
  PR:           kern/148857
  MFC After:    3 days

Modified:
  head/sys/netinet6/nd6.c

Modified: head/sys/netinet6/nd6.c
==============================================================================
--- head/sys/netinet6/nd6.c     Tue Dec  7 22:43:25 2010        (r216276)
+++ head/sys/netinet6/nd6.c     Tue Dec  7 22:43:29 2010        (r216277)
@@ -1053,15 +1053,6 @@ nd6_free(struct llentry *ln, int gc)
                        return (next);
                }
 
-               if (ln->ln_router || dr) {
-                       /*
-                        * rt6_flush must be called whether or not the neighbor
-                        * is in the Default Router List.
-                        * See a corresponding comment in nd6_na_input().
-                        */
-                       rt6_flush(&L3_ADDR_SIN6(ln)->sin6_addr, ifp);
-               }
-
                if (dr) {
                        /*
                         * Unreachablity of a router might affect the default
@@ -1077,8 +1068,28 @@ nd6_free(struct llentry *ln, int gc)
                         * or the entry itself will be deleted.
                         */
                        ln->ln_state = ND6_LLINFO_INCOMPLETE;
+               }
+
+               if (ln->ln_router || dr) {
 
                        /*
+                        * We need to unlock to avoid a LOR with rt6_flush() 
with the
+                        * rnh and for the calls to pfxlist_onlink_check() and
+                        * defrouter_select() in the block further down for 
calls
+                        * into nd6_lookup().  We still hold a ref.
+                        */
+                       LLE_WUNLOCK(ln);
+
+                       /*
+                        * rt6_flush must be called whether or not the neighbor
+                        * is in the Default Router List.
+                        * See a corresponding comment in nd6_na_input().
+                        */
+                       rt6_flush(&L3_ADDR_SIN6(ln)->sin6_addr, ifp);
+               }
+
+               if (dr) {
+                       /*
                         * Since defrouter_select() does not affect the
                         * on-link determination and MIP6 needs the check
                         * before the default router selection, we perform
@@ -1087,13 +1098,13 @@ nd6_free(struct llentry *ln, int gc)
                        pfxlist_onlink_check();
 
                        /*
-                        * Refresh default router list.  Have to unlock as
-                        * it calls into nd6_lookup(), still holding a ref.
+                        * Refresh default router list.
                         */
-                       LLE_WUNLOCK(ln);
                        defrouter_select();
-                       LLE_WLOCK(ln);
                }
+
+               if (ln->ln_router || dr)
+                       LLE_WLOCK(ln);
        }
 
        /*
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