Data abort, External abort.. How can i find cause????

Hi, experts

I'm developing Secure OS on A57/53 bit.LITTLE SoC. But as you know.. Cuz i'm really beginner..

I beg your wisdom...

Current situation is :

• For making a TA. Bring the related data from REE and Mapping TEE side's NON-SECURE memory. (Data are information for executing file (Elf section info ... etc).
• Copying that Mapping data on SECURE memory. and UnMapping former area.

Using above way the TA runs but ONLY 17 times.

at 18 times it occurs External Abort (DABT) and remain below information.

• dfsr:0xc06, prev mode: SVC MODE

i have no idea why this happen...? Could you give me a your merciful answers and idea???

Thank you.....;