Bug 213191 - Module versioning + Missing CRC in symvers + export tracepoints
Summary: Module versioning + Missing CRC in symvers + export tracepoints
Status: NEW
Alias: None
Product: Other
Classification: Unclassified
Component: Modules (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: other_modules
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2021-05-24 10:10 UTC by Chaitanya T K
Modified: 2021-05-24 10:10 UTC (History)
0 users

See Also:
Kernel Version:
Subsystem:
Regression: No
Bisected commit-id:


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Description Chaitanya T K 2021-05-24 10:10:06 UTC
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/
Comment 1 Chaitanya T K 2021-05-24 10:10:47 UTC
LKML discussion with no response is here https://lkml.org/lkml/2021/5/4/233

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