Re: Latest net-next from GIT panic

W dniu 2017-09-21 o 13:31, Paweł Staszewski pisze:

W dniu 2017-09-21 o 13:03, Eric Dumazet pisze:

quoted

OK we have two problems here

1) We need to unify skb_dst_force()  ( for net tree )

2) Vlan devices should try to correctly handle IFF_XMIT_DST_RELEASE from
lower device. This will considerably help your performance.


For 1), this is what I had in mind, can you try it ?

Thanks a lot !

diff --git a/include/net/dst.h b/include/net/dst.h

index 
93568bd0a3520bb7402f04d90cf04ac99c81cfbe..f23851eeaad917e8dafc06b58d23a2575405c894 
100644

--- a/include/net/dst.h
+++ b/include/net/dst.h

@@ -271,7 +271,7 @@ static inline void dst_use_noref(struct dst_entry 

*dst, unsigned long time)
  static inline struct dst_entry *dst_clone(struct dst_entry *dst)
  {
      if (dst)
-        atomic_inc(&dst->__refcnt);
+        dst_hold(dst);
      return dst;
  }
  @@ -311,21 +311,6 @@ static inline void skb_dst_copy(struct sk_buff 
*nskb, const struct sk_buff *oskb
      __skb_dst_copy(nskb, oskb->_skb_refdst);
  }
  -/**
- * skb_dst_force - makes sure skb dst is refcounted
- * @skb: buffer
- *
- * If dst is not yet refcounted, let's do it
- */
-static inline void skb_dst_force(struct sk_buff *skb)
-{
-    if (skb_dst_is_noref(skb)) {
-        WARN_ON(!rcu_read_lock_held());
-        skb->_skb_refdst &= ~SKB_DST_NOREF;
-        dst_clone(skb_dst(skb));
-    }
-}
-
  /**
   * dst_hold_safe - Take a reference on a dst if possible
   * @dst: pointer to dst entry

@@ -356,6 +341,23 @@ static inline void skb_dst_force_safe(struct 

sk_buff *skb)
      }
  }
  +/**
+ * skb_dst_force - makes sure skb dst is refcounted
+ * @skb: buffer
+ *
+ * If dst is not yet refcounted, let's do it
+ */
+static inline void skb_dst_force(struct sk_buff *skb)
+{
+    if (skb_dst_is_noref(skb)) {
+        struct dst_entry *dst = skb_dst(skb);
+
+        WARN_ON(!rcu_read_lock_held());
+        if (!dst_hold_safe(dst))
+            dst = NULL;
+        skb->_skb_refdst = (unsigned long)dst;
+    }
+}
    /**
   *    __skb_tunnel_rx - prepare skb for rx reinsert

Patch applied - soo far no problems - and no warnings in dmesg

ok after adding patch all is working from now for about 1 hour of normal 
traffic witc all bgp sessions connected and about 600k prefixes in kernel.