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Zend: Fix stack overflow crash in recursive function #22524

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Zend: Fix stack overflow crash in recursive function #22524

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Zend: Fix stack overflow crash in recursive function
arshidkv12 Jun 30, 2026
6ee395a
Zend: Fix stack overflow crash in recursive function
arshidkv12 Jun 30, 2026
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24 changes: 24 additions & 0 deletions Zend/tests/gh22521.phpt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,24 @@
--TEST--
GH-22521: Infinite recursion inside try/catch should not crash unpredictably
--INI--
memory_limit=8G
--SKIPIF--
<?php
if (!getenv('RUN_RESOURCE_HEAVY_TESTS')) die('skip resource-heavy test');
if (getenv('SKIP_SLOW_TESTS')) die('skip slow test');
if (PHP_INT_SIZE != 8) die('skip 64-bit only');
?>
--FILE--
<?php
try {
function foo() {
foo();
}
foo();
} catch (\Throwable $_ffl_e) {
echo "Caught throwable\n";
}
echo "End\n";
?>
--EXPECTF--
Fatal error: Allowed memory size of %d bytes exhausted at %s:%d (tried to allocate %d bytes) in %s on line %d
3 changes: 3 additions & 0 deletions Zend/zend_builtin_functions.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1940,6 +1940,9 @@ ZEND_API void zend_fetch_debug_backtrace(zval *return_value, int skip_last, int
/* For frameless calls we add an additional frame for the call itself. */
if (ZEND_USER_CODE(call->func->type)) {
const zend_op *opline = call->opline;
if (UNEXPECTED(!opline)) {
goto not_frameless_call;
}

@arnaud-lb arnaud-lb Jun 30, 2026

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This may be the wrong fix: A NULL opline implies that we are missing a SAVE_OPLINE() somewhere in the engine.

if (!ZEND_OP_IS_FRAMELESS_ICALL(opline->opcode)) {
goto not_frameless_call;
}
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