undefined reference to `mbedtls_debug_set_threshold' when MBEDTLS_DEBUG is enabled

[laperie]

Describe the bug
Cannot enable debugging of MBEDTLS. Something is rotten in the state of Denmark. (C) Shakespeare

To Reproduce
Steps to reproduce the behavior:

1. in Default for TLS_PEER_VERIFY socket option are set to required, may lead to confusion when running samples against self-signed certs #14632, enable MBEDTLS_DEBUG
2. build
3. See error

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots or console output

/opt/zephyr-sdk/i586-zephyr-elf/bin/../lib/gcc/i586-zephyr-elf/8.3.0/../../../../i586-zephyr-elf/bin/ld: libzephyr.a(sockets_tls.c.obj): in function `tls_init':
/home/laperie/workspace/zephyr/zephyr/subsys/net/lib/sockets/sockets_tls.c:289: undefined reference to `mbedtls_debug_set_threshold'
collect2: error: ld returned 1 exit status
zephyr/CMakeFiles/zephyr_prebuilt.dir/build.make:99: recipe for target 'zephyr/zephyr_prebuilt.elf' failed
make[2]: *** [zephyr/zephyr_prebuilt.elf] Error 1

Environment (please complete the following information):
Linux
0.10.0 SDK

[rlubos]

Hi @laperie, I've seen this issue before. It seems that make does not rebuild mbedTLS in case Zephyr configuration is changed (in this case mbedTLS debug enabled). When I used make, I forced it to rebuild entire project with make clean && make after changing mbedTLS configuration.

Apparently this is not an issue when using ninja - it seems to understand better what needs to be rebuilt.

[laperie]

Hi @laperie, I've seen this issue before. It seems that make does not rebuild mbedTLS in case Zephyr configuration is changed (in this case mbedTLS debug enabled). When I used make, I forced it to rebuild entire project with make clean && make after changing mbedTLS configuration.

Cannot confirm that, sorry -- same symptoms no matter what you use to build the sample. Problem is likely elsewhere...

[jukkar]

I have not used public server like in the example as I do not have direct internet access from my test host. So I used simple python https server with self certified certificate, could that self cert be the culprit here?

[rlubos]

@jukkar I suppose the above comment reffered to #14632?

[jukkar]

Ah, sorry, I seemed to have commented wrong issue :)

[jukkar]

I just tried this and did not see any issues -> closing.

[hraftery]

Adding the mysterious CONFIG_MBEDTLS_DEBUG_C fixes it for me.