Re: Hang when booting guest kernels compiled with clang after SRSO mitigations

[Borislav Petkov]

On Thu, Aug 10, 2023 at 06:40:56AM -0700, Nathan Chancellor wrote:
>   6.5.0-rc5-00039-g138bcddb86d8 (nathan@dev-arch.thelio-3990X) (x86_64-linux-gcc (GCC) 13.2.0, GNU ld (GNU Binutils) 2.41) #1 SMP PREEMPT_DYNAMIC Wed Aug  9 17:34:43 MST 2023

Mine:

Linux version 6.5.0-rc5+ (root@vh) (gcc (Debian 10.2.1-3) 10.2.1 20201224, GNU ld (GNU Binutils for Debian) 2.40) #1 SMP PREEMPT_DYNAMIC Thu Aug 10 16:13:54 CEST 2023

...

[    0.083541] Speculative Return Stack Overflow: Mitigation: safe RET

> Guest kernel string:
> 
>   6.5.0-rc5 (nathan@dev-arch.thelio-3990X) (ClangBuiltLinux clang version 16.0.6 (https://github.com/llvm/llvm-project 7cbf1a2591520c2491aa35339f227775f4d3adf6), GNU ld (GNU Binutils) 2.41.50.20230809) #1 SMP PREEMPT_DYNAMIC Wed Aug  9 16:54:33 MST 2023
> 

Mine:

[    0.000000] Linux version 6.5.0-rc5 (root@vh) (Debian clang version 14.0.6, GNU ld (GNU Binutils for Debian) 2.40) #1 SMP PREEMPT_DYNAMIC Thu Aug 10 13:22:30 CEST 2023

Guest and host are up and running.

There's something else missing.

Your host gcc is 13, maybe I should update...

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette