TWI driver reading out of bounds memory. "Can't compute CFA for this frame."

RE: TWI driver reading out of bounds memory. "Can't compute CFA for this frame."

Eliot Stock — Sat, 17 Sep 2016 11:51:38 GMT

@Einar Thorsrud I can't reproduce this sorry, it's happened only once so far. But yes, I do use -g3 in my CFLAGS.

RE: TWI driver reading out of bounds memory. "Can't compute CFA for this frame."

Eliot Stock — Sat, 17 Sep 2016 11:49:14 GMT

@RK OK, I'm confused about StackTop vs. StackLimit, then. I was looking at __StackLimit (0x20007800). Which is __StackTop less the size of .stack_dummy. Why do I have a stack dummy and what is it?

RE: TWI driver reading out of bounds memory. "Can't compute CFA for this frame."

RK — Tue, 13 Sep 2016 13:20:03 GMT

in what way is 0x20007dda out of bounds? Your stack top is 0x20008000 and it's of size 0x800 so it runs from 0x20007800 to 0x20008000 which makes 0x20007dda just 1/3 the way down from the top of the stack. Looking in the standard gcc_startup_nrf51.S it shows the first entry in the vector table is __StackTop, so that's the start of your stack.

RE: TWI driver reading out of bounds memory. "Can't compute CFA for this frame."

Einar Thorsrud — Tue, 13 Sep 2016 12:01:11 GMT

Do you see the same out of bounds address if you check p_twi in the beginning of twi_transfer() in nrf_drv_twi.c? Also, regarding the "Can't compute CFA for this frame.": Have you compiling with -g3?