[php-src] Issue #8282: oops, unknown child exited with code 0

Issue: https://github.com/php/php-src/issues/8282 Author: derekrprice ### Description The following code: No code needed. Just start php-fpm. Resulted in this output: ``` 2022-03-30T18:30:39.378169050Z + php-fpm 2022-03-30T18:30:39.437828786Z [30-Mar-2022 18:30:39] NOTICE: fpm is running, pid 1 2022-03-30T18:30:39.438452091Z [30-Mar-2022 18:30:39] NOTICE: ready to handle connections 2022-03-30T18:30:52.079271289Z 127.0.0.1 - 30/Mar/2022:18:30:52 +0000 "GET /status" 200 2022-03-30T18:30:59.523826247Z 127.0.0.1 - 30/Mar/2022:18:30:59 +0000 "GET /status" 200 2022-03-30T18:30:59.527060870Z [30-Mar-2022 18:30:59] ALERT: oops, unknown child (91) exited with code 0. Please open a (https://github.com/php/php-src/issues). 2022-03-30T18:31:04.811549398Z 127.0.0.1 - 30/Mar/2022:18:31:04 +0000 "GET /status" 200 2022-03-30T18:31:04.813610713Z [30-Mar-2022 18:31:04] ALERT: oops, unknown child (104) exited with code 0. Please open a bug report (https://github.com/php/php-src/issues). 2022-03-30T18:31:04.828971625Z [30-Mar-2022 18:31:04] NOTICE: Finishing ... 2022-03-30T18:31:04.831711045Z [30-Mar-2022 18:31:04] NOTICE: exiting, bye-bye! ``` But I expected it to not exit. More details: This was happening with PHP 7.4 and Laravel 8. The docker image that this was running in came up fine under Kubernetes (k8s) 1.19, but began crashing like this with k8s 1.20. I have a good dozen other services running Laravel 6.5 in the same php:7.4-fpm base image with no problems in k8s 1.20. A second service running Laravel 8 on php:7.4-fpm is running into the same problem. I have now upgraded my k8s cluster all the way to 1.22.6 and the problem has not gone away. I proceeded to update to the php:8.0.17-fpm docker base image and have updated all my composer-installed packages to their latest minor versions. I am at somewhat of a loss for how to debug. It appears that this must be some sort of interaction specific to Laravel 8 and k8s 1.20+, but the php-fpm error message said to open a ticket here, so I'm hoping that you might be able to provide some insight. Thanks! ### PHP Version PHP 8.0.17 ### Operating System Kubernetes 1.20+ Laravel 8