zts build segfault

[brettmc]

Describe the bug I'm not sure if this is meant to work or not, but the php+apache setup we use has thread-safe builds of php modules. I built apm-agent-php with thread-safety, I see startup messages from the module, but it does nothing (no debug/trace logs) when a script is executed. However, if I phpinfo() it will segfault.

OS: centos 7 php: 7.4.20 apm-agent-php: 1.1

To Reproduce Steps to reproduce the behavior:

1. Build zts module:

zts-phpize
CFLAGS="-std=gnu99" ./configure --enable-elastic_apm --with-php-config=/usr/bin/zts-php-config
make clean
make install
echo "extension=elastic_apm.so" > /etc/php-zts.d/98-elastic-apm.ini
echo "elastic_apm.bootstrap_php_part_file=/opt/elastic/apm-agent-php/src/bootstrap_php_part.php" >> /etc/php-zts.d/98-elastic-apm.ini

2. Then call phpinfo() in a script
3. See segfault
4. (or) <?php echo "hello world";
5. No tracing happens

Expected behavior Tracing and no segfault

If it helps, here is a Dockerfile which demonstrates the issue:

FROM centos:7
CMD ["/usr/sbin/httpd", "-DFOREGROUND"]

#php + apache 2.4 (NB that codeit.guru provides an updated apache, but also causes zts variants of modules to be loaded)
RUN yum install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm \
      http://rpms.remirepo.net/enterprise/remi-release-7.rpm \
      unzip \
      wget \
    && cd /etc/yum.repos.d \
    && wget https://repo.codeit.guru/codeit.el`rpm -q --qf "%{VERSION}" $(rpm -q --whatprovides redhat-release)`.repo \
    && yum-config-manager --enable remi-php74 \
    && yum install -y \
      php \
    && yum clean all

#build elastic apm-agent-php zts
RUN mkdir -p /opt/elastic/ \
 && cd /tmp \
 && wget https://github.com/elastic/apm-agent-php/archive/refs/tags/v1.1.zip \
 && unzip v1.1.zip -d /opt/elastic/ \
 && mv /opt/elastic/apm-agent-php-1.1 /opt/elastic/apm-agent-php \
 && rm *.zip \
 && cd /opt/elastic/apm-agent-php/src/ext \
 && yum install -y php-devel curl-devel \
 && zts-phpize \
 && CFLAGS="-std=gnu99" ./configure --enable-elastic_apm --with-php-config=/usr/bin/zts-php-config \
 && make clean \
 && make \
 && make install \
 && echo "extension=elastic_apm.so" > /etc/php-zts.d/98-elastic-apm.ini \
 && echo "elastic_apm.bootstrap_php_part_file=/opt/elastic/apm-agent-php/src/bootstrap_php_part.php" >> /etc/php-zts.d/98-elastic-apm.ini

# test files, redirect apache logs
RUN echo "<?php phpinfo();" > /var/www/html/index.php \
 && echo "<?php echo 'hello world';" > /var/www/html/test.php \
 && sed -i 's/logs\/access_log/\/dev\/stdout/' /etc/httpd/conf/httpd.conf \
 && sed -i 's/logs\/error_log/\/dev\/stderr/' /etc/httpd/conf/httpd.conf

[brettmc]

FYI this is super-low priority for us, I changed our docker image to not use zts to work around this issue.

[SergeyKleyman]

We don't have near term plans to support ZTS mode.