diff --git a/include/haproxy/pattern-t.h b/include/haproxy/pattern-t.h
index aa3a17878..b84c7e71e 100644
--- a/include/haproxy/pattern-t.h
+++ b/include/haproxy/pattern-t.h
@@ -207,6 +207,7 @@ struct pattern_expr {
 	struct eb_root pattern_tree;  /* may be used for lookup in large datasets */
 	struct eb_root pattern_tree_2;  /* may be used for different types */
 	int mflags;                     /* flags relative to the parsing or matching method. */
+	uint32_t refcount;            /* refcount used to know if the expr can be deleted or not */
 	__decl_thread(HA_RWLOCK_T lock);               /* lock used to protect patterns */
 };
 
@@ -216,7 +217,6 @@ struct pattern_expr {
  */
 struct pattern_expr_list {
 	struct list list; /* Used for chaining pattern_expr in pattern_head. */
-	int do_free;
 	struct pattern_expr *expr; /* The used expr. */
 };
 
diff --git a/src/pattern.c b/src/pattern.c
index 346fe59d5..7a2a15acc 100644
--- a/src/pattern.c
+++ b/src/pattern.c
@@ -2190,19 +2190,14 @@ struct pattern_expr *pattern_new_expr(struct pattern_head *head, struct pat_ref
 		expr->ref = ref;
 
 		HA_RWLOCK_INIT(&expr->lock);
-
-		/* We must free this pattern if it is no more used. */
-		list->do_free = 1;
 	}
 	else {
-		/* If the pattern used already exists, it is already linked
-		 * with ref and we must not free it.
-		 */
-		list->do_free = 0;
 		if (reuse)
 			*reuse = 1;
 	}
 
+	HA_ATOMIC_INC(&expr->refcount);
+
 	/* The new list element reference the pattern_expr. */
 	list->expr = expr;
 
@@ -2583,7 +2578,7 @@ void pattern_prune(struct pattern_head *head)
 
 	list_for_each_entry_safe(list, safe, &head->head, list) {
 		LIST_DELETE(&list->list);
-		if (list->do_free) {
+		if (HA_ATOMIC_SUB_FETCH(&list->expr->refcount, 1) == 0) {
 			LIST_DELETE(&list->expr->list);
 			HA_RWLOCK_WRLOCK(PATEXP_LOCK, &list->expr->lock);
 			head->prune(list->expr);