Quoting Vlad Buslov (2022-01-31 12:26:47)

On Fri 28 Jan 2022 at 19:01, Antoine Tenart [off-list ref] wrote:

quoted

I finally had some time to look at this. Does the diff below fix your
issue?

Yes, with the patch applied I'm no longer able to reproduce memory leak.
Thanks for fixing this!

Thanks for testing. I'll send a formal patch, can I add your Tested-by?

Also, do you know how to trigger the following code path in OVS
https://elixir.bootlin.com/linux/latest/source/net/openvswitch/actions.c#L944
? Would be good (not required) to test it, to ensure the fix doesn't
break it.

Thanks,
Antoine

quoted

diff --git a/include/net/dst_metadata.h b/include/net/dst_metadata.h
index 14efa0ded75d..90a7a4daea9c 100644
--- a/include/net/dst_metadata.h
+++ b/include/net/dst_metadata.h

@@ -110,8 +110,8 @@ static inline struct metadata_dst *tun_rx_dst(int md_size)
 static inline struct metadata_dst *tun_dst_unclone(struct sk_buff *skb)
 {
        struct metadata_dst *md_dst = skb_metadata_dst(skb);
-       int md_size;
        struct metadata_dst *new_md;
+       int md_size, ret;
 
        if (!md_dst || md_dst->type != METADATA_IP_TUNNEL)
                return ERR_PTR(-EINVAL);

@@ -123,8 +123,15 @@ static inline struct metadata_dst *tun_dst_unclone(struct sk_buff *skb)
 
        memcpy(&new_md->u.tun_info, &md_dst->u.tun_info,
               sizeof(struct ip_tunnel_info) + md_size);
+#ifdef CONFIG_DST_CACHE
+       ret = dst_cache_init(&new_md->u.tun_info.dst_cache, GFP_ATOMIC);
+       if (ret) {
+               metadata_dst_free(new_md);
+               return ERR_PTR(ret);
+       }
+#endif
+
        skb_dst_drop(skb);
-       dst_hold(&new_md->dst);
        skb_dst_set(skb, &new_md->dst);
        return new_md;
 }