[tor-relays] nf_conntrack: falling back to vmalloc.

Starting with 12th ojf June I do get at my tor relay a lot of sslog entries like :

Jul 14 14:35:49 tor-relay kernel: [68591.883586] nf_conntrack: falling back to vmalloc. Jul 14 14:35:49 tor-relay kernel: [68591.884749] nf_conntrack: falling back to vmalloc. Jul 14 14:41:11 tor-relay kernel: [68913.618544] nf_conntrack: falling back to vmalloc.

Now I'm wondering if this is by any chance related to Tor ?