From: Maria Matejka <mq@ucw.cz>
Date: Wed, 19 Jun 2024 10:02:34 +0000 (+0200)
Subject: Fixed a race condition in rcu-domain blocking
X-Git-Tag: v3.0.0~126
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9be90c0f84e8ffce6bbd89222843e9da3d634f68;p=thirdparty%2Fbird.git

Fixed a race condition in rcu-domain blocking
---

diff --git a/sysdep/unix/domain.c b/sysdep/unix/domain.c
index 2817455fd..4e6d8a61c 100644
--- a/sysdep/unix/domain.c
+++ b/sysdep/unix/domain.c
@@ -137,6 +137,9 @@ void do_lock(struct domain_generic *dg, struct domain_generic **lsp)
 
 void do_unlock(struct domain_generic *dg, struct domain_generic **lsp)
 {
+  if (dg->forbidden_when_reading_rcu)
+    ASSERT_DIE(rcu_blocked--);
+
   if ((char *) lsp - (char *) &locking_stack != dg->order)
     bug("Trying to unlock on bad position: order=%u, lsp=%p, base=%p", dg->order, lsp, &locking_stack);
 
@@ -150,6 +153,5 @@ void do_unlock(struct domain_generic *dg, struct domain_generic **lsp)
   dg->prev = NULL;
   pthread_mutex_unlock(&dg->mutex);
 
-  if (dg->forbidden_when_reading_rcu)
-    ASSERT_DIE(rcu_blocked--);
+  /* From here on, the dg pointer is invalid! */
 }