linux-kernel - Re: Module versioning + Missing CRC in symvers + export tracepoints

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Message-ID: <CABPxzY+USNoiFDO8VYtLzFDK-0+PU1wD8ah7KGPWGZ+uEStH-g@mail.gmail.com>
Date:   Tue, 4 May 2021 17:22:01 +0530
From:   Krishna Chaitanya <chaitanya.mgit@...il.com>
To:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        mmarek@...e.cz, arnd@...db.de
Subject: Re: Module versioning + Missing CRC in symvers + export tracepoints

On Tue, Apr 20, 2021 at 6:26 PM Krishna Chaitanya
<chaitanya.mgit@...il.com> wrote:
>
> 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, 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
>
> Any ideas?
Adding people from this
https://patchwork.kernel.org/project/linux-kbuild/patch/CA+55aFxCKgTrh1gS-cMyhBa0QoLW2DL2+DYxOAcA-Bd15H15vg@mail.gmail.com/
thread to throw some light on non-asm version of the issue.