These glibc free() errors usually mean in C/C++ programs that someone is mixing stack-based memory blocks with allocated memory blocks. It's tricky, because older gcc versions or glibc versions do not enforce these errors. It helps to write better programs, but it's a pain to find what causes the problem.
In your case the problem is likely to be introduced by one of the extension. Of course you have to make sure that the problem doesn't show up for your plain PHP installation.
linux