Bug 213191

Hi,

I am seeing an issue of no CRC being generated in the Module.symvers for a
driver module even when CONFIG_MODVERSIONS Is enabled, this causes
modpost warnings about missing versioning.

The module in questions only exports tracepoint related symbols (as
struct tracepoint is part of the module CRC), I have seen this with other modules also e.g.iwlwifi with CONFIG_MODVERSIONS.

Though I am trying on 5.12.-rc2, also, seeing this issue with older kernels with CONFIG_MODVERSIONS enabled e.g. 4.15.0 (Ubuntu 18.04), Below are a couple of snippets to demonstrate the issue.

modpost warnings
===============

WARNING: modpost: EXPORT symbol "__tracepoint_iwlwifi_dev_ucode_event"
[drivers/net/wireless/intel/iwlwifi//iwlwifi.ko] version generation
failed, symbol will not be versioned.
WARNING: modpost: EXPORT symbol "iwl_remove_notification"
[drivers/net/wireless/intel/iwlwifi//iwlwifi.ko] version generation
failed, symbol will not be versioned.


Module.symvers (after modpost)
==============
0x00000000      iwl_remove_notification
drivers/net/wireless/intel/iwlwifi//iwlwifi     EXPORT_SYMBOL_GPL
0x00000000      __tracepoint_iwlwifi_dev_ucode_event
drivers/net/wireless/intel/iwlwifi//iwlwifi     EXPORT_SYMBOL

A similar issue but for ASM is reported here https://patchwork.kernel.org/project/linux-kbuild/patch/CA+55aFxCKgTrh1gS-cMyhBa0QoLW2DL2+DYxOAcA-Bd15H15vg@mail.gmail.com/