diff --git a/NEWS b/NEWS
index ab372893ce661..993bdda130cd9 100644
--- a/NEWS
+++ b/NEWS
@@ -16,6 +16,10 @@ PHP                                                                        NEWS
     with a given skeleton, locale, collapse type and identity fallback.
     (BogdanUngureanu)
 
+- Opcache:
+  . Fixed bug GH-20051 (apache2 shutdowns when restart is requested during
+    preloading). (Arnaud, welcomycozyhom)
+
 - Standard:
   . Fixed bug GH-19926 (reset internal pointer earlier while splicing array
     while COW violation flag is still set). (alexandre-daubois)
diff --git a/ext/opcache/ZendAccelerator.c b/ext/opcache/ZendAccelerator.c
index 9ef74973a4dff..e6a2b90e8fffc 100644
--- a/ext/opcache/ZendAccelerator.c
+++ b/ext/opcache/ZendAccelerator.c
@@ -4524,16 +4524,6 @@ static void preload_load(size_t orig_map_ptr_static_last)
 		}
 	}
 
-	if (EG(zend_constants)) {
-		EG(persistent_constants_count) = EG(zend_constants)->nNumUsed;
-	}
-	if (EG(function_table)) {
-		EG(persistent_functions_count) = EG(function_table)->nNumUsed;
-	}
-	if (EG(class_table)) {
-		EG(persistent_classes_count)   = EG(class_table)->nNumUsed;
-	}
-
 	size_t old_map_ptr_last = CG(map_ptr_last);
 	if (zend_map_ptr_static_last != ZCSG(map_ptr_static_last) || old_map_ptr_last != ZCSG(map_ptr_last)) {
 		CG(map_ptr_last) = ZCSG(map_ptr_last);
@@ -4803,6 +4793,12 @@ static zend_result accel_preload(const char *config, bool in_child)
 
 		preload_load(orig_map_ptr_static_last);
 
+		/* Update persistent counts, as shutdown will discard anything past
+		 * that, and these tables are aliases to global ones at this point. */
+		EG(persistent_functions_count) = EG(function_table)->nNumUsed;
+		EG(persistent_classes_count)   = EG(class_table)->nNumUsed;
+		EG(persistent_constants_count) = EG(zend_constants)->nNumUsed;
+
 		/* Store individual scripts with unlinked classes */
 		HANDLE_BLOCK_INTERRUPTIONS();
 		SHM_UNPROTECT();
@@ -5094,13 +5090,45 @@ static zend_result accel_finish_startup(void)
 
 		exit(ret == SUCCESS ? 0 : 1);
 	} else { /* parent */
-		int status;
+# ifdef HAVE_SIGPROCMASK
+		/* Interrupting the waitpid() call below with a signal would cause the
+		 * process to exit. This is fine when the signal disposition is set to
+		 * terminate the process, but not otherwise.
+		 * When running the apache2handler, preloading is performed in the
+		 * control process. SIGUSR1 and SIGHUP are used to tell the control
+		 * process to restart children. Exiting when these signals are received
+		 * would unexpectedly shutdown the server instead of restarting it.
+		 * Block the USR1 and HUP signals from being delivered during the
+		 * syscall when running the apache2handler SAPI, as these are not
+		 * supposed to terminate the process. See GH-20051. */
+		bool is_apache2handler = strcmp(sapi_module.name, "apache2handler") == 0;
+		sigset_t set, oldset;
+		if (is_apache2handler) {
+			if (sigemptyset(&set)
+					|| sigaddset(&set, SIGUSR1)
+					|| sigaddset(&set, SIGHUP)) {
+				ZEND_UNREACHABLE();
+			}
+			if (sigprocmask(SIG_BLOCK, &set, &oldset)) {
+				ZEND_UNREACHABLE();
+			}
+		}
+# endif
 
+		int status;
 		if (waitpid(pid, &status, 0) < 0) {
 			zend_shared_alloc_unlock();
 			zend_accel_error_noreturn(ACCEL_LOG_FATAL, "Preloading failed to waitpid(%d)", pid);
 		}
 
+# ifdef HAVE_SIGPROCMASK
+		if (is_apache2handler) {
+			if (sigprocmask(SIG_SETMASK, &oldset, NULL)) {
+				ZEND_UNREACHABLE();
+			}
+		}
+# endif
+
 		if (ZCSG(preload_script)) {
 			preload_load(zend_map_ptr_static_last);
 		}
diff --git a/sapi/fpm/fpm/zlog.c b/sapi/fpm/fpm/zlog.c
index 803a768234bd6..b34d455e6bd6c 100644
--- a/sapi/fpm/fpm/zlog.c
+++ b/sapi/fpm/fpm/zlog.c
@@ -466,7 +466,7 @@ static ssize_t zlog_stream_buf_flush(struct zlog_stream *stream) /* {{{ */
 	}
 #endif
 
-	if (external_logger != NULL) {
+	if (stream->use_external_logger) {
 		external_logger(stream->flags & ZLOG_LEVEL_MASK,
 				stream->buf.data + stream->prefix_len, stream->len - stream->prefix_len);
 	}
@@ -539,9 +539,11 @@ static inline void zlog_stream_init_internal(
 	stream->fd = fd > -1 ? fd : STDERR_FILENO;
 	stream->buf_init_size = capacity;
 	if (flags & ZLOG_ACCESS_LOG) {
+		stream->use_external_logger = 0;
 		stream->use_buffer = 1;
 		stream->use_stderr = fd < 0;
 	} else {
+		stream->use_external_logger = external_logger != NULL;
 		stream->use_buffer = zlog_buffering || external_logger != NULL || stream->use_syslog;
 		stream->use_stderr = fd < 0 ||
 				(
diff --git a/sapi/fpm/fpm/zlog.h b/sapi/fpm/fpm/zlog.h
index 6886a0ae807da..8b4a80155f073 100644
--- a/sapi/fpm/fpm/zlog.h
+++ b/sapi/fpm/fpm/zlog.h
@@ -77,6 +77,7 @@ struct zlog_stream {
 	unsigned int decorate:1;
 	unsigned int is_stdout:1;
 	unsigned int over_limit:1;
+	unsigned int use_external_logger:1;
 	int fd;
 	int line;
 	int child_pid;
diff --git a/sapi/fpm/tests/gh19989-access-log-fcgi-stderr.phpt b/sapi/fpm/tests/gh19989-access-log-fcgi-stderr.phpt
new file mode 100644
index 0000000000000..6875774de3fac
--- /dev/null
+++ b/sapi/fpm/tests/gh19989-access-log-fcgi-stderr.phpt
@@ -0,0 +1,47 @@
+--TEST--
+FPM: GH-19989 - Access log going to fcgi error stream
+--SKIPIF--
+<?php include "skipif.inc"; ?>
+--FILE--
+<?php
+
+require_once "tester.inc";
+
+$src = <<<EOT
+<?php
+echo "OK";
+EOT;
+
+$cfg = <<<EOT
+[global]
+error_log = {{RFILE:LOG:ERR}}
+pid = {{RFILE:PID}}
+[unconfined]
+listen = {{ADDR}}
+access.log = {{RFILE:LOG:ACC}}
+access.format = "'%m %r%Q%q' %s"
+pm = static
+pm.max_children = 2
+EOT;
+
+$prefix = __DIR__;
+$tester = new FPM\Tester($cfg, $src);
+$tester->start(['--prefix', $prefix]);
+$tester->expectLogStartNotices();
+$response = $tester->request()->expectBody('OK');
+$response->expectNoError();
+$tester->expectAccessLog("'GET /gh19989-access-log-fcgi-stderr.src.php' 200");
+$tester->terminate();
+$tester->expectLogTerminatingNotices();
+$tester->close();
+$tester->checkAccessLog();
+
+?>
+Done
+--EXPECT--
+Done
+--CLEAN--
+<?php
+require_once "tester.inc";
+FPM\Tester::clean();
+?>