How to acquire memory from a running Linux system

Dumping memory on Linux system can be cumbersome especially that the behavior might be different among different GNU/Linux distribution or Linux kernel version. In the early days, the easiest was to dump the memory from the memory device (/dev/mem) but over time the access was more and more restricted in order to avoid malicious process to directly access the kernel memory directly. The kernel option CONFIG_STRICT_DEVMEM was introduced in kernel version 2.6 and upper (2.6.36–2.6.39, 3.0–3.8, 3.8+HEAD). So you'll need to use a Linux kernel module in order to acquire memory.

fmem