3 stack limit tests failing on Alpinelinux PHP 8.3

[andypost]

Description

Stack size tests added in #9104

The following tests started to fail when PHP using --enable-zend-test

• Zend/tests/stack_limit/stack_limit_007.phpt
• Zend/tests/stack_limit/stack_limit_011.phpt
• Zend/tests/stack_limit/stack_limit_012.phpt

Resulted in this output:

TEST 4094/16862 [Zend/tests/stack_limit/stack_limit_007.phpt]
========DIFF========
001- array(4) {
002-   ["base"]=>
003-   string(%d) "0x%x"
004-   ["max_size"]=>
005-   string(%d) "0x%x"
006-   ["position"]=>
007-   string(%d) "0x%x"
008-   ["EG(stack_limit)"]=>
009-   string(%d) "0x%x"
010- }
011- Maximum call stack size of %d bytes reached. Infinite recursion?
012- Try executed: 1
001+ Fatal error: Maximum call stack size of 81920 bytes reached during compilation. Try splitting expression in /home/buildozer/aports/testing/php83/src/php-8.3.0RC6/Zend/tests/stack_limit/stack_limit_007.php on line 3
========DONE========

TEST 4098/16862 [Zend/tests/stack_limit/stack_limit_011.phpt]
========DIFF========
001- array(4) {
002-   ["base"]=>
003-   string(%d) "0x%x"
004-   ["max_size"]=>
005-   string(%d) "0x%x"
006-   ["position"]=>
007-   string(%d) "0x%x"
008-   ["EG(stack_limit)"]=>
009-   string(%d) "0x%x"
010- }
011- Maximum call stack size of %d bytes reached. Infinite recursion?
012- Previous: Maximum call stack size of %d bytes reached. Infinite recursion?
001+ Fatal error: Maximum call stack size of 81920 bytes reached during compilation. Try splitting expression in /home/buildozer/aports/testing/php83/src/php-8.3.0RC6/Zend/tests/stack_limit/stack_limit_011.php on line 3
========DONE========

TEST 4099/16862 [Zend/tests/stack_limit/stack_limit_012.phpt]
========DIFF========
001- array(4) {
002-   ["base"]=>
003-   string(%d) "0x%x"
004-   ["max_size"]=>
005-   string(%d) "0x%x"
006-   ["position"]=>
007-   string(%d) "0x%x"
008-   ["EG(stack_limit)"]=>
009-   string(%d) "0x%x"
010- }
011- 
     Fatal error: Maximum call stack size of %d bytes reached during compilation. Try splitting expression in %s on line %d
========DONE========

PHP Version

PHP 8.3.0RC5

Operating System

Alpinelinux

[andypost]

Probably @arnaud-lb is the author

[andypost]

One more test failed in CI (maybe because of some concurrency)

TEST 4090/16862 [Zend/tests/stack_limit/stack_limit_003.phpt]
========DIFF========
001- array(4) {
002-   ["base"]=>
003-   string(%d) "0x%x"
004-   ["max_size"]=>
005-   string(%d) "0x%x"
006-   ["position"]=>
007-   string(%d) "0x%x"
008-   ["EG(stack_limit)"]=>
009-   string(%d) "0x%x"
010- }
011- Maximum call stack size of %d bytes reached. Infinite recursion?
012- Maximum call stack size of %d bytes reached. Infinite recursion?
013- Maximum call stack size of %d bytes reached. Infinite recursion?
001+ Fatal error: Maximum call stack size of 81920 bytes reached during compilation. Try splitting expression in /builds/alpine/aports/testing/php83/src/php-8.3.0RC6/Zend/tests/stack_limit/stack_limit_003.php on line 3
========DONE========

[arnaud-lb]

I could not reproduce this locally on Alpine 3.18 x86_64. I've configured php with CC=clang ./configure --disable-all --enable-zend-test --with-external-pcre.

The stack size in the error message Maximum call stack size of 81920 bytes reached during compilation looks suspicious. Either the stack size detection has gone wrong, or the stack size of the process is really small.

Could you share the output of these commands ?

$ ulimit -s
$ sapi/cli/php -r 'var_dump(zend_test_zend_call_stack_get());'

[andypost]

It is reproducible only on ppc64le arch, maybe because of byte-order

[andypost]

The whole run with diff in https://gitlab.alpinelinux.org/alpine/aports/-/jobs/1176577

[andypost]

Default musl value is 128kb (80k prior to 1.1.21) according to https://wiki.musl-libc.org/functional-differences-from-glibc.html#Thread-stack-size

[arnaud-lb]

Thank you. I was able to reproduce the issue in a ppc64le VM on tests stack_limit_011.phpt and stack_limit_012.phpt.

These tests set a stack limit that is too low, so it is reached too soon on this arch.

The 81920 bytes in the error message is actually correct: this is 128KiB minus zend.reserved_stack_size (ZEND_ALLOCA_MAX_SIZE+16*1024 by default). The error message is confusing.

Could you confirm that this branch resolves the issue? PHP-8.3...arnaud-lb:php-src:gh12643

[andypost]

Thank you a lot!
Tests passed https://gitlab.alpinelinux.org/alpine/aports/-/jobs/1178440

PS: good to know that bug was in tests)

[bukka]

@arnaud-lb might be worth to create a PR and merge it...

[andypost]

Thank you