From f5eb19febedf5663b3ba9617ecc03cdf94b6df9c Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen@gmail.com>
Date: Sun, 16 Aug 2026 11:23:11 +0100
Subject: [PATCH 1/3] ext/opcache: opcache.interned_strings_buffer per FPM pool
 crashed on restart.

Fix #23288

The directive was still accepted once the shared interned string table
had been sized from the master php.ini, so a diverging pool value made
the next restart run accel_interned_strings_restore_state() against a
table that was never allocated. Reject post-startup changes like
opcache.memory_consumption and gate the restore on the shared table
state instead of the per-process directive.
---
 ext/opcache/ZendAccelerator.c         | 2 +-
 ext/opcache/zend_accelerator_module.c | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/ext/opcache/ZendAccelerator.c b/ext/opcache/ZendAccelerator.c
index a2d964c15070..70f3d8313638 100644
--- a/ext/opcache/ZendAccelerator.c
+++ b/ext/opcache/ZendAccelerator.c
@@ -2715,7 +2715,7 @@ ZEND_RINIT_FUNCTION(zend_accelerator)
 				zend_reset_cache_vars();
 				zend_accel_hash_clean(&ZCSG(hash));
 
-				if (ZCG(accel_directives).interned_strings_buffer) {
+				if (ZCSG(interned_strings).saved_top) {
 					accel_interned_strings_restore_state();
 				}
 
diff --git a/ext/opcache/zend_accelerator_module.c b/ext/opcache/zend_accelerator_module.c
index ffa09aaf9e67..2fb7e775bb34 100644
--- a/ext/opcache/zend_accelerator_module.c
+++ b/ext/opcache/zend_accelerator_module.c
@@ -93,6 +93,11 @@ static ZEND_INI_MH(OnUpdateMemoryConsumption)
 
 static ZEND_INI_MH(OnUpdateInternedStringsBuffer)
 {
+	if (accel_startup_ok) {
+		zend_accel_error(ACCEL_LOG_WARNING, "opcache.interned_strings_buffer cannot be changed when OPcache is already set up.");
+		return FAILURE;
+	}
+
 	zend_long *p = (zend_long *) ZEND_INI_GET_ADDR();
 	zend_long size = zend_ini_parse_quantity_warn(new_value, entry->name);
 

From cede67419a61a39fbc1e4a0b5cba486f43e916a1 Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen@gmail.com>
Date: Sun, 16 Aug 2026 12:13:13 +0100
Subject: [PATCH 2/3] add fpm test

---
 ...-opcache-interned-strings-buffer-pool.phpt | 53 +++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 sapi/fpm/tests/gh23288-opcache-interned-strings-buffer-pool.phpt

diff --git a/sapi/fpm/tests/gh23288-opcache-interned-strings-buffer-pool.phpt b/sapi/fpm/tests/gh23288-opcache-interned-strings-buffer-pool.phpt
new file mode 100644
index 000000000000..b64e919b105b
--- /dev/null
+++ b/sapi/fpm/tests/gh23288-opcache-interned-strings-buffer-pool.phpt
@@ -0,0 +1,53 @@
+--TEST--
+FPM: GH-23288 - opcache.interned_strings_buffer overridden per pool must not crash on restart
+--EXTENSIONS--
+opcache
+--SKIPIF--
+<?php include "skipif.inc"; ?>
+--FILE--
+<?php
+
+require_once "tester.inc";
+
+$cfg = <<<EOT
+[global]
+error_log = {{FILE:LOG}}
+[unconfined]
+listen = {{ADDR}}
+pm = static
+pm.max_children = 1
+php_admin_value[opcache.enable] = 1
+php_admin_value[opcache.enable_cli] = 1
+php_admin_value[opcache.interned_strings_buffer] = 8
+EOT;
+
+$code = <<<EOT
+<?php
+opcache_reset();
+opcache_reset();
+echo "ok";
+EOT;
+
+$tester = new FPM\Tester($cfg, $code);
+$tester->start(iniEntries: [
+    'opcache.enable' => '1',
+    'opcache.enable_cli' => '1',
+    'opcache.interned_strings_buffer' => '0',
+]);
+$tester->expectLogStartNotices();
+$tester->request()->expectBody('ok');
+$tester->request()->expectBody('ok');
+$tester->request()->expectBody('ok');
+$tester->terminate();
+$tester->expectLogTerminatingNotices();
+$tester->close();
+
+?>
+Done
+--EXPECT--
+Done
+--CLEAN--
+<?php
+require_once "tester.inc";
+FPM\Tester::clean();
+?>

From bfab8efe8d0c8acde9edf499bb3f3fcc9904e284 Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen@gmail.com>
Date: Sun, 16 Aug 2026 12:37:04 +0100
Subject: [PATCH 3/3] fix test attempt

---
 .../gh23288-opcache-interned-strings-buffer-pool.phpt | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/sapi/fpm/tests/gh23288-opcache-interned-strings-buffer-pool.phpt b/sapi/fpm/tests/gh23288-opcache-interned-strings-buffer-pool.phpt
index b64e919b105b..8f48b3a8c209 100644
--- a/sapi/fpm/tests/gh23288-opcache-interned-strings-buffer-pool.phpt
+++ b/sapi/fpm/tests/gh23288-opcache-interned-strings-buffer-pool.phpt
@@ -16,8 +16,6 @@ error_log = {{FILE:LOG}}
 listen = {{ADDR}}
 pm = static
 pm.max_children = 1
-php_admin_value[opcache.enable] = 1
-php_admin_value[opcache.enable_cli] = 1
 php_admin_value[opcache.interned_strings_buffer] = 8
 EOT;
 
@@ -28,12 +26,11 @@ opcache_reset();
 echo "ok";
 EOT;
 
+$opcache = ini_get('extension_dir') . DIRECTORY_SEPARATOR . 'opcache.' . PHP_SHLIB_SUFFIX;
+$extraArgs = is_file($opcache) ? ['-dzend_extension=' . $opcache] : [];
+
 $tester = new FPM\Tester($cfg, $code);
-$tester->start(iniEntries: [
-    'opcache.enable' => '1',
-    'opcache.enable_cli' => '1',
-    'opcache.interned_strings_buffer' => '0',
-]);
+$tester->start($extraArgs, iniEntries: ['opcache.interned_strings_buffer' => '0']);
 $tester->expectLogStartNotices();
 $tester->request()->expectBody('ok');
 $tester->request()->expectBody('ok');