lib: don't create circular lists (fixes 6d83113)

LISTNODE_DETACH doesn't clear out the node, and LISTNODE_ATTACH doesn't
set ->next (since it assumes a fresh/zeroed listnode).  As a result, the
new listnode_move_to_tail() created a nice circular list, in turn
crashing ospfd in ospf_write() later.

Reported-by: Martin Winter <mwinter@netdef.org>
Fixes: 6d83113 ("ospfd: Tweak previous iface RR write patch to avoid free/malloc & redundant log")
Cc: Paul Jakma <paul@opensourcerouting.org>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
Acked-by: Greg Troxel <gdt@ir.bbn.com>
Acked-by: Dinesh Dutt <ddutt@cumulusnetworks.com>
Acked-by: Vincent JARDIN <vincent.jardin@6wind.com>
(cherry picked from commit 1c6db0d2da34044ddfb42665fda8a3387ecc451d)

diff --git a/lib/linklist.h b/lib/linklist.h
index 24a9e20698a55b94a75d3c43390cba9b045c115b..88f4a0391209cf4e8c8506fe23f1833235bab2f4 100644 (file)
--- a/lib/linklist.h
+++ b/lib/linklist.h
@@ -112,6 +112,7 @@ extern void list_add_list (struct list *, struct list *);
 #define LISTNODE_ATTACH(L,N) \
   do { \
     (N)->prev = (L)->tail; \
+    (N)->next = NULL; \
     if ((L)->head == NULL) \
       (L)->head = (N); \
     else \