From 8a1dc18bbcf11a2eb36cfd3dbb290976d87284d1 Mon Sep 17 00:00:00 2001
From: Matthias van de Meent <boekewurm+postgres@gmail.com>
Date: Wed, 29 Apr 2026 12:10:44 +0200
Subject: [PATCH v1] Assert ProcSignal is initialized before its dependents

---
 src/backend/access/transam/xlog.c            | 1 +
 src/backend/replication/logical/logicalctl.c | 1 +
 src/backend/storage/ipc/procsignal.c         | 8 ++++++++
 src/include/storage/procsignal.h             | 5 +++++
 4 files changed, 15 insertions(+)

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index e39af79c03b..63e84b00cec 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -4960,6 +4960,7 @@ SetDataChecksumsOff(void)
 void
 InitLocalDataChecksumState(void)
 {
+	Assert(ProcSignalIsInitialized());
 	SpinLockAcquire(&XLogCtl->info_lck);
 	SetLocalDataChecksumState(XLogCtl->data_checksum_version);
 	SpinLockRelease(&XLogCtl->info_lck);
diff --git a/src/backend/replication/logical/logicalctl.c b/src/backend/replication/logical/logicalctl.c
index 72f68ec58ef..80308b619a4 100644
--- a/src/backend/replication/logical/logicalctl.c
+++ b/src/backend/replication/logical/logicalctl.c
@@ -173,6 +173,7 @@ update_xlog_logical_info(void)
 void
 InitializeProcessXLogLogicalInfo(void)
 {
+	Assert(ProcSignalIsInitialized());
 	update_xlog_logical_info();
 }
 
diff --git a/src/backend/storage/ipc/procsignal.c b/src/backend/storage/ipc/procsignal.c
index b0681ca0ae2..71a0b25e49e 100644
--- a/src/backend/storage/ipc/procsignal.c
+++ b/src/backend/storage/ipc/procsignal.c
@@ -232,6 +232,14 @@ ProcSignalInit(const uint8 *cancel_key, int cancel_key_len)
 	on_shmem_exit(CleanupProcSignalState, (Datum) 0);
 }
 
+#ifdef USE_ASSERT_CHECKING
+bool
+ProcSignalIsInitialized(void)
+{
+	return MyProcSignalSlot != NULL;
+}
+#endif
+
 /*
  * CleanupProcSignalState
  *		Remove current process from ProcSignal mechanism
diff --git a/src/include/storage/procsignal.h b/src/include/storage/procsignal.h
index aaa158bfd66..1d2290c6975 100644
--- a/src/include/storage/procsignal.h
+++ b/src/include/storage/procsignal.h
@@ -87,4 +87,9 @@ typedef struct ProcSignalHeader ProcSignalHeader;
 extern PGDLLIMPORT ProcSignalHeader *ProcSignal;
 #endif
 
+#ifdef USE_ASSERT_CHECKING
+extern bool ProcSignalIsInitialized(void);
+#endif
+
+
 #endif							/* PROCSIGNAL_H */
-- 
2.50.1 (Apple Git-155)

