OBJTOOL Build error

[Greg KH]

On Thu, Nov 24, 2022 at 01:48:08PM -0500, John Aron wrote:
> Hello -
> 
>  
> 
> I have an idea of where to begin: our kernel code compiles and works on Red
> Hat, CentOS, and Fedora. In Ubuntu 20.04, I have an error.
> 
>  
> 
> root at form:/home/john/thor-linux/Kernel/ubuntu20.04# make
> 
> rmmod: ERROR: Module thor is not currently loaded
> 
> make: [Makefile:7: all] Error 1 (ignored)
> 
> make[1]: Entering directory '/usr/src/linux-headers-5.4.0-131-generic'
> 
>   CC [M]  /home/john/thor-linux/Kernel/ubuntu22.04/thor.o
> 
> /home/john/thor-linux/Kernel/ubuntu22.04/thor.o: warning: objtool:
> _Controller_process_response_map()+0x1b3:    unreachable instruction
> 
>   Building modules, stage 2.
> 
>   MODPOST 1 modules
> 
>   CC [M]  /home/john/thor-linux/Kernel/ubuntu22.04/thor.mod.o
> 
>   LD [M]  /home/john/thor-linux/Kernel/ubuntu22.04/thor.ko
> 
> make[1]: Leaving directory '/usr/src/linux-headers-5.4.0-131-generic'
> 
> make[1]: Entering directory '/usr/src/linux-headers-5.4.0-131-generic'
> 
>   CLEAN   /home/john/thor-linux/Kernel/ubuntu22.04/Module.symvers
> 
> make[1]: Leaving directory '/usr/src/linux-headers-5.4.0-131-generic'
> 
> #@sudo dmesg -C
> 
> #@sudo insmod /usr/local/etc/thor.ko
> 
> filename:       /usr/local/etc/thor.ko
> 
> version:        0.1
> 
> description:    THOR KMOD
> 
> author:         Aronetics
> 
> license:        GPL
> 
> srcversion:     BC856FA85DB2FEFD38A1B2A
> 
> depends:
> 
> retpoline:      Y
> 
> name:           thor
> 
> vermagic:       5.4.0-131-generic SMP mod_unload modversions
> 
> #@sudo dmesg
> 
> root at form:/home/john/thor-linux/Kernel/ubuntu20.04#
> <mailto:root at form:/home/john/thor-linux/Kernel/ubuntu20.04#> 
> 
>  
> 
> Every 2.0s: tail -n30 /var/lib/dkms/thor/1.0.1/build/make.log
> 
>  
> 
> DKMS make.log for thor-1.0.1 for kernel 5.4.0-131-generic (x86_64)
> 
> Thu 24 Nov 2022 01:10:33 PM EST
> 
> make: Entering directory '/usr/src/linux-headers-5.4.0-131-generic'
> 
>   CC [M]  /var/lib/dkms/thor/1.0.1/build/thor.o
> 
> /var/lib/dkms/thor/1.0.1/build/thor.o: warning: objtool:
> _Controller_process_response_map()+0x1b3: unreachable instruction
> 
>   Building modules, stage 2.
> 
>   MODPOST 1 modules
> 
>   CC [M]  /var/lib/dkms/thor/1.0.1/build/thor.mod.o
> 
>   LD [M]  /var/lib/dkms/thor/1.0.1/build/thor.ko
> 
> make: Leaving directory '/usr/src/linux-headers-5.4.0-131-generic'
> 
>  
> 
> Is this an error in objtool on Ubuntu within
> /usr/src/linux-headers-5.4.0-${26-130}/tools/objtool ?

Do you have a pointer to your code anywhere?  Do you have .S files in
it, or is it all C files?

And did you ask the Canonical developers about this?  You should have a
support contract you are paying for with them, so why not use that?

thanks,

greg k-h