Comment 31 for bug 1585614

Same issue

This morning, a security update for libc has been automatically
deployed on all our servers running 14.04 LTS.

unattended-upgrades-dpkg_2016-05-26_06:36:05.829399.log:Unpacking libc6-dev:amd64
unattended-upgrades-dpkg_2016-05-26_06:36:05.829399.log:Unpacking libc-dev-bin
unattended-upgrades-dpkg_2016-05-26_06:36:05.829399.log:Unpacking libc-bin
unattended-upgrades-dpkg_2016-05-26_06:36:05.829399.log:Unpacking libc6:amd64
unattended-upgrades-dpkg_2016-05-26_06:36:05.829399.log:Unpacking multiarch-support

On one of our web servers (only one??) Apache (2.4.7-1ubuntu4.9) has stopped working
after the unattended upgrades of libc6. When Apache received the signal SIGUSR1.

This did not impact any other web server with identical version of all softwares
(aligned with Ansible) ?! -- at least in the beginning of the day...

Later on at 12:52 we did "apachectl graceful" on all our web servers and all apache servers stopped responding until we restart them with "service apache2 restart".

[Thu May 26 06:35:36.222660 2016] [mpm_worker:notice] [pid 6318:tid 140737354041216]
AH00297: SIGUSR1 received. Doing graceful restart

[Thu May 26 06:35:36.231321 2016] [:alert] [pid 16293:tid 140737354041216]
(4)Interrupted system call: FastCGI: read() from pipe failed (0)

[Thu May 26 06:35:36.231395 2016] [:alert] [pid 16293:tid 140737354041216]
(4)Interrupted system call: FastCGI: the PM is shutting down, Apache seems to have disappeared - bye
apache2: Syntax error on line 140 of /etc/apache2/apache2.conf: Syntax error on line 2 of /etc/apache2/mods-enabled/security2.load: Cannot load libxml2.so.2 into server: /lib/x86_64-linux-gnu/libm.so.6: symbol __strtold_nan, version GLIBC_PRIVATE not defined in file libc.so.6 with link time reference