RHEL 7.2 で Apache httpd プロセスがクラッシュし (43)Identifier removed: AH00144: couldn't grab the accept mutex メッセージが出力される

Issue

Apache httpd プロセスがクラッシュし、以下の mutex エラーが RHEL 7.2 に出力されます。

[mpm_prefork:emerg] [pid 9629] (43)Identifier removed:AH00144: couldn't grab the accept mutex
[mpm_prefork:emerg] [pid 9659] (43)Identifier removed:AH00144: couldn't grab the accept mutex
[mpm_prefork:emerg] [pid 9623] (43)Identifier removed:AH00144: couldn't grab the accept mutex
[mpm_prefork:emerg] [pid 9950] (43)Identifier removed:AH00144: couldn't grab the accept mutex
[mpm_prefork:emerg] [pid 9626] (43)Identifier removed:AH00144: couldn't grab the accept mutex
[core:alert] [pid 25888] AH00050:Child 9623 returned a Fatal error...Apache is exiting!
[mpm_prefork:emerg] [pid 9628] (22)Invalid argument:AH00146: couldn't release the accept mutex