From 5ce0bf5281d15b0a6f0d3ecef3c7f5c301def08c Mon Sep 17 00:00:00 2001
From: "W.C.A. Wijngaards" <wouter@nlnetlabs.nl>
Date: Tue, 14 Apr 2026 15:34:59 +0200
Subject: [PATCH] - Fix #1017: memory corruption related core dumps.   When
 alloc_reg_obtain has an empty list, return a new allocation.

---
 doc/Changelog | 4 ++++
 util/alloc.c  | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/doc/Changelog b/doc/Changelog
index 9e38cc515..761e2a4f6 100644
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -1,3 +1,7 @@
+14 April 2026: Wouter
+	- Fix #1017: memory corruption related core dumps.
+	  When alloc_reg_obtain has an empty list, return a new allocation.
+
 13 April 2026: Yorgos
 	- Update the documentation of 'max-query-restarts' in the man page.
 
diff --git a/util/alloc.c b/util/alloc.c
index 9a99246f5..e4e1aeb4d 100644
--- a/util/alloc.c
+++ b/util/alloc.c
@@ -328,7 +328,7 @@ size_t alloc_get_mem(struct alloc_cache* alloc)
 struct regional* 
 alloc_reg_obtain(struct alloc_cache* alloc)
 {
-	if(alloc->num_reg_blocks > 0) {
+	if(alloc->num_reg_blocks > 0 && alloc->reg_list) {
 		struct regional* r = alloc->reg_list;
 		alloc->reg_list = (struct regional*)r->next;
 		r->next = NULL;