[php-src] Issue #9910: opcache + MPM ITK might cause apache2 to hang

Issue: https://github.com/php/php-src/issues/9910 Author: diab303 ### Description This is referring to the bug that is present since at least 5.6. It still happens in 7.4 (just confirmed) and the same code is present in 8.x so I assume the behaviour is the same there, too. Apache + PHP + MPM_ITK hangs at random intervals spamming "Cannot kill process" in the apache error log. The original bug report is here: https://bugs.php.net/bug.php?id=76482 The fix looks pretty trivial (break the loop when kill fails) but I'm not sure if it would cause other problems. Quoting the bug history: > It was reported in 5.6.36 but the bug is in 7.1 (reproduced here) and by looking into source > code also in current 7.3 branch. >Not only mpm itk is affected but any MPM which switches child processes to different UIDs (via >setuid()). Other example is mod_ruid2 - >https://github.com/mind04/mod-ruid2/issues/17 >kill_all_lockers() has a loop which never ends if killing fails as kill(mem_usage_check->l_pid, SIGKILL) returns EPERM in errno. >There is ``` if (!success) { /* errno is not ESRCH or we ran out of tries to kill the locker */ ZCSG(force_restart_time) = time(NULL); /* restore forced restart request */ /* cannot kill the locker, bail out with error */ zend_accel_error(ACCEL_LOG_ERROR, "Cannot kill process %d: %s!", mem_usage_check->l_pid, strerror(errno)); } ``` >but it doesn't break the loop. Is brake missing here? ### PHP Version PHP 7.4 ### Operating System Debian 11