Question about the debugging example?

[Zhou Yu]

hi, I'm try to get the stack trace when my nacl application crash. So I'm looking for the debugging  example in pepper_49 tutorial. But when I run the tutorial I got this info:

Stack Trace

[0]            clang-newlib/Release/debugging_x86_64.o NexeMain + 0x40

[1] .../lib/libppapi_stub.a(thread_creator_ccf263e1.o) __nacl_register_thread_creator + 0xa60

I'm not sure is this correct? I was expecting something like 

[0]  layer5

[1] layer4

[2] layer3....

etc.

Thanks.