From: Maria Matejka <mq@ucw.cz>
Date: Thu, 27 Jun 2024 07:08:01 +0000 (+0200)
Subject: fixup! Forbid locking altogether when RCU reader is active
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e96c44e32d0b95eecdff9db344617fd24027eeba;p=thirdparty%2Fbird.git

fixup! Forbid locking altogether when RCU reader is active
---

diff --git a/sysdep/unix/alloc.c b/sysdep/unix/alloc.c
index 1cf41a5bb..0432b9e26 100644
--- a/sysdep/unix/alloc.c
+++ b/sysdep/unix/alloc.c
@@ -215,6 +215,14 @@ alloc_page(void)
   /* Reinstate the stack with zero */
   PAGE_STACK_PUT(NULL);
 
+  if (rcu_read_active())
+  {
+    /* We can't lock and we actually shouldn't alloc either when rcu is active
+     * but that's a quest for another day. */
+  }
+  else
+  {
+
   /* If there is any free page kept cold, we use that. */
   LOCK_DOMAIN(resource, empty_pages_domain);
   if (empty_pages) {
@@ -244,6 +252,8 @@ alloc_page(void)
   if (fp)
     return fp;
 
+  }
+
   /* And in the worst case, allocate some new pages by mmap() */
   void *ptr = alloc_sys_page();
   ajlog(ptr, NULL, 0, AJT_ALLOC_MMAP);