apparent memory leak using posix_memalign

[DGelling]

when allocating and deallocating memory of sufficient size with posix_memalign while keeping smaller allocations done with malloc, a memory leak happens. This only appears when using certain ranges of allocation sizes, and can cause the system to lock up when running out of memory while only having a few megabytes allocated on a 16GB ram machine.

lsb_release -rd:

Description: Ubuntu 18.04.3 LTS
Release: 18.04

apt-cache policy libc6:

libc6:
  Installed: 2.27-3ubuntu1
  Candidate: 2.27-3ubuntu1
  Version table:
 *** 2.27-3ubuntu1 500
        500 http://archive.ubuntu.com/ubuntu bionic/main amd64 Packages
        100 /var/lib/dpkg/status

see attached for a small program that will trigger the memory leak

I have not tried this on other distros, so don't know if this is ubuntu specific

[DGelling (dgelling)]

Forgot to add:

I compiled with gcc 7.4:

gcc (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

using the following command line:

$ gcc -O0 -g -o memleak memleak.c