Could not insert module: Exec format error

Could not insert module: Exec format error

[Santosh Sivaraj]

I am very much new to Rust for Linux. My first attempt to build the kernel with
rust support, and insert the example rust module failed with the following
error.

santosh@x86-vm ~ $ modprobe rust_example.ko 
modprobe: FATAL: Module rust_example.ko not found in directory /lib/modules/5.12.0-rc3+
santosh@x86-vm ~ $ modprobe rust_example
modprobe: ERROR: could not insert 'rust_example': Operation not permitted
santosh@x86-vm ~ $ sudo modprobe rust_example
modprobe: ERROR: could not insert 'rust_example': Exec format error
santosh@x86-vm ~ $ sudo modprobe rust_example_2 
modprobe: ERROR: could not insert 'rust_example_2': Exec format error
santosh@x86-vm ~ $ sudo modprobe rust_example_3
modprobe: ERROR: could not insert 'rust_example_3': Exec format error
santosh@x86-vm ~ $

I followed the 'quick-start.rst' by the letter. What am I doing wrong?

I am building the kernel on a x86 host and running it on a x86 qemu VM.

Thanks,
Santosh

Re: Could not insert module: Exec format error

[Miguel Ojeda]

Hi Santosh,

On Sat, Mar 20, 2021 at 12:25 PM Santosh Sivaraj <santosh@fossix.org> wrote:
>
> I am building the kernel on a x86 host and running it on a x86 qemu VM.

Is that by chance 32-bit x86?

Cheers,
Miguel

Re: Could not insert module: Exec format error

[Santosh Sivaraj]

Hi Miguel,

Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> writes:

> Hi Santosh,
>
> On Sat, Mar 20, 2021 at 12:25 PM Santosh Sivaraj <santosh@fossix.org> wrote:
>>
>> I am building the kernel on a x86 host and running it on a x86 qemu VM.
>
> Is that by chance 32-bit x86?

No, it is a 64-bit x86 guest. I also saw this in the dmesg:

[   43.409639] module: rust_example_3: Unknown rela relocation: 9

Googling took me to https://github.com/rust-lang/rust/issues/57390, and tried to
pass `-Z plt=y` in quiet_cmd_rustc_procmacro, but still the same issue.

Thanks,
Santosh

>
> Cheers,
> Miguel

Re: Could not insert module: Exec format error

[Miguel Ojeda]

On Mon, Mar 22, 2021 at 3:31 AM Santosh Sivaraj <santosh@fossix.org> wrote:
>
> No, it is a 64-bit x86 guest. I also saw this in the dmesg:
>
> [   43.409639] module: rust_example_3: Unknown rela relocation: 9

Ah, we saw this with the latest nightlies -- I'll take a look soon.
Please give a go to the 2021-02-20, that one should work.

Cheers,
Miguel