Netlink: fix occasional netlink hangs on busy machines

sysdep/linux/netlink.c

@@ -1497,6 +1497,7 @@ nl_async_hook(sock *sk, uint size UNUSED)
 	   *  One day we might react to it by asking for route table
 	   *  scan in near future.
 	   */
+	  log(L_WARN "Kernel dropped some netlink messages, will resync on next scan.");
 	  return 1;	/* More data are likely to be ready */
 	}
       else if (errno != EWOULDBLOCK)

sysdep/unix/io.c

@@ -2238,6 +2238,7 @@ io_loop(void)
 	      if (pfd[s->index].revents & (POLLHUP | POLLERR))
 		{
 		  sk_err(s, pfd[s->index].revents);
+		  if (s != current_sock)
 		    goto next2;
 		}