zebra: Log how we got to this failure.

When a filter function fails to work correctly, we get an
error message that something has gone wrong.  Unfortunately
we may not have any clues as to where the decode failure
happened.  Add a backtrace to give us a clue.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>

diff --git a/zebra/kernel_netlink.c b/zebra/kernel_netlink.c
index 6d164cfdabf700e8a91c801f87f3b1e7c8c5604c..7334c8094a3001c0bf4ccde57cb0ff43842c3b14 100644 (file)
--- a/zebra/kernel_netlink.c
+++ b/zebra/kernel_netlink.c
@@ -772,6 +772,7 @@ int netlink_parse_info(int (*filter)(struct nlmsghdr *, ns_id_t, int),
                        error = (*filter)(h, zns->ns_id, startup);
                        if (error < 0) {
                                zlog_err("%s filter function error", nl->name);
+                               zlog_backtrace(LOG_ERR);
                                ret = error;
                        }
                }