From: Maria Matejka <mq@ucw.cz>
Date: Tue, 10 Dec 2024 09:52:52 +0000 (+0100)
Subject: Nest: fixed a race-condition between import and export
X-Git-Tag: v3.0.0~31
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bc15f0b9c704dcac85ac471d96509e866dc5b09b;p=thirdparty%2Fbird.git

Nest: fixed a race-condition between import and export

There was a leaking stack pointer to the global memory.
Fixed by making that temporary structure thread local static.
---

diff --git a/nest/rt-table.c b/nest/rt-table.c
index e24973112..cd37d9478 100644
--- a/nest/rt-table.c
+++ b/nest/rt-table.c
@@ -1964,10 +1964,8 @@ rte_recalculate(struct rtable_private *table, struct rt_import_hook *c, struct n
     }
 
   /* We need to add a spinlock sentinel to the beginning */
-  struct rte_storage local_sentinel = {
-    .flags = REF_OBSOLETE,
-    .next = old_best_stored,
-  };
+  _Thread_local static struct rte_storage local_sentinel = { .flags = REF_OBSOLETE, };
+  atomic_store_explicit(&local_sentinel.next, old_best_stored, memory_order_release);
   atomic_store_explicit(&net->routes, &local_sentinel, memory_order_release);
 
   /* Mark also the old route as obsolete. */