From e0cd2e7953dcb06a8c0f6707c98bd3aae8487b63 Mon Sep 17 00:00:00 2001
From: Nick Vatamaniuc <vatamane@gmail.com>
Date: Mon, 5 Feb 2024 19:02:33 +0000
Subject: [PATCH] DEBUG: Extra check for fast heap range check

---
 erts/emulator/beam/erl_message.c | 5 +++--
 erts/emulator/beam/erl_message.h | 2 +-
 erts/emulator/beam/erl_process.c | 2 +-
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/erts/emulator/beam/erl_message.c b/erts/emulator/beam/erl_message.c
index c5c6b63f0884..e2af79cc1f0e 100644
--- a/erts/emulator/beam/erl_message.c
+++ b/erts/emulator/beam/erl_message.c
@@ -1676,13 +1676,14 @@ erts_check_circular_offheap(Process *p)
     slow = fast = p->off_heap.first;
 
     while (fast) {
+        if(ErtsInBetween(fast, p->htop, p->hend)) return 1;
         fast = fast->next;
-        if (fast == slow) return 0;
+        if (fast == slow) return 2;
 
         if (++cnt & 1) {
             slow = slow->next;
         }
     }
 
-    return 1;
+    return 0;
 }
diff --git a/erts/emulator/beam/erl_message.h b/erts/emulator/beam/erl_message.h
index 94838785ed05..4ccabac01efa 100644
--- a/erts/emulator/beam/erl_message.h
+++ b/erts/emulator/beam/erl_message.h
@@ -643,7 +643,7 @@ int erts_check_circular_offheap(Process *p);
         erts_check_circular_offheap(P);                 \
     } while (0)
 #else
-#  define ERTS_CHK_MBUF_SZ(P) ERTS_ASSERT(erts_check_circular_offheap(P))
+#  define ERTS_CHK_MBUF_SZ(P) ERTS_ASSERT((erts_check_circular_offheap(P)==0))
 #endif
 
 #define ERTS_FOREACH_SIG_PRIVQS(PROC, MVAR, CODE)                       \
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index bd6c3689b926..ca4f0c769948 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -13360,7 +13360,7 @@ erts_proc_exit_handle_dist_monitor(ErtsMonitor *mon, void *vctxt, Sint reds)
         hp = erts_produce_heap(&factory, watcher_sz, 0);
         ERTS_CHK_MBUF_SZ(c_p);
         watcher = copy_struct(watcher, watcher_sz, &hp, factory.off_heap);
-        if(!erts_check_circular_offheap(c_p)) {
+        if(erts_check_circular_offheap(c_p)) {
            fflush(stdout);
            fflush(stderr);
            fprintf(stderr, "XXXXX %s:%s:%d \n", __FILE__, __func__, __LINE__);