Skip to content

Fix GH-20483: ASAN stack overflow with small fiber.stack_size INI value. #20495

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
wants to merge 3 commits into from
Closed

Fix GH-20483: ASAN stack overflow with small fiber.stack_size INI value. #20495

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
51f15da
Fix GH-20483: ASAN stack overflow with small fiber.stack_size INI value.
devnexen Nov 15, 2025
b92286c
feedback
devnexen Nov 15, 2025
b24b903
add test
devnexen Nov 15, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
16 changes: 16 additions & 0 deletions Zend/tests/fibers/gh20483.phpt
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,16 @@
--TEST--
GH-20483 (ASAN stack overflow with small fiber.stack_size INI value)
--INI--
fiber.stack_size=1024
--FILE--
<?php
$callback = function () {};
$fiber = new Fiber($callback);
try {
$fiber->start();
} catch (Exception $e) {
echo $e->getMessage() . "\n";
}
?>
--EXPECTF--
Fiber stack size is too small, it needs to be at least %d bytes
7 changes: 6 additions & 1 deletion Zend/zend_fibers.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -207,7 +207,12 @@ static zend_fiber_stack *zend_fiber_stack_allocate(size_t size)
{
void *pointer;
const size_t page_size = zend_fiber_get_page_size();
const size_t minimum_stack_size = page_size + ZEND_FIBER_GUARD_PAGES * page_size;
const size_t minimum_stack_size = page_size + ZEND_FIBER_GUARD_PAGES * page_size
#ifdef __SANITIZE_ADDRESS__
// necessary correction due to ASAN redzones
* 6
#endif
;

if (size < minimum_stack_size) {
zend_throw_exception_ex(NULL, 0, "Fiber stack size is too small, it needs to be at least %zu bytes", minimum_stack_size);
Expand Down
Loading