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From: Greg KH <greg@kroah.com>
To: Tomek The Messenger <tomekthemessenger@gmail.com>
Cc: kernelnewbies@kernelnewbies.org
Subject: Re: Unknown symbol reboot_mode
Date: Mon, 23 Mar 2020 11:46:53 +0100	[thread overview]
Message-ID: <20200323104653.GA522243@kroah.com> (raw)
In-Reply-To: <CAA4NGyvS=wBr4+y+LFa0C+XbfGDhwesqMwk6aQ0TbVCjDHC_5A@mail.gmail.com>

On Mon, Mar 23, 2020 at 11:27:50AM +0100, Tomek The Messenger wrote:
> Hi
> When I insert external kernel module which is compiled out of tree I got
> error:
> 
> root:/run# insmod ./my_module.ko
> [  137.443823] my_module: Unknown symbol reboot_mode (err 0)
> 
> I investigated that I have attached in my my_module.c file:
> #include <linux/reboot.h>
> and in this file we have:
> extern enum reboot_mode reboot_mode;
> However reboot_mode symbol is not exported with macro EXPORT_SYMBOL_GPL.
> Probably this is the reason why symbol is not seen in my module.

That is correct.

> Then why
> the same issue doesn't occur here:
> /arch/arm/kernel/setup.c
> /arch/arm64/kernel/process.c
> Those linux files also use global variable reboot_mode.

Because those files are not built as a kernel module, but rather
directly into the kernel image.

hope this helps,

greg k-h

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      reply	other threads:[~2020-03-23 10:48 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-23 10:27 Unknown symbol reboot_mode Tomek The Messenger
2020-03-23 10:46 ` Greg KH [this message]

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