How to test RAM on embedded ARM system? (Linux, no console)

I get a lot of memory dumps in dmesg, It seems to me every time the OS is trying to use any more than about 100 MB of RAM weird things are happening.

How can I test RAM on ARM, on running Linux system? For a standard server, I'dI'd run memtest x86, but that's for x86, and is loaded instead of OS.

Here, I've got ARM embedded system (Kirkwood CPU), without console - I can only access it after it boots. I know that test in such environment would be less than perfect, but it's always something.