Re: [tip:x86/seves] BUILD SUCCESS WITH WARNING e6eb15c9ba3165698488ae5c34920eea20eaa38e

Josh Poimboeuf
2020-09-15T18:59:47Z

On Tue, Sep 15, 2020 at 06:05:54PM +0200, Borislav Petkov wrote:
> On Tue, Sep 15, 2020 at 10:18:16PM +0800, Rong Chen wrote:
> > On Tue, Sep 15, 2020 at 03:55:19PM +0200, Borislav Petkov wrote:
> > > On Tue, Sep 15, 2020 at 09:42:56PM +0800, kernel test robot wrote:
> > > > tree/branch: https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git x86/seves
> > > > branch HEAD: e6eb15c9ba3165698488ae5c34920eea20eaa38e KVM: nSVM: Avoid freeing uninitialized pointers in svm_set_nested_state()
> > > >
> > > > Warning in current branch:
> > > >
> > > > arch/x86/kernel/sev-es.o: warning: objtool: ist_exc_vmm_communication()+0x12: unreachable instruction
> > > >
> > > > Warning ids grouped by kconfigs:
> > > >
> > > > clang_recent_errors
> > > > `-- x86_64-randconfig-r001-20200913
> > > > `-- arch-x86-kernel-sev-es.o:warning:objtool:ist_exc_vmm_communication():unreachable-instruction
>
> Ok, I can't trigger this with gcc-9, gcc-10 and clang-10.
>
> .config below says clang-12 so it could be some experimental
> bug^Wfeature :)
>
> peterz says this has been fixed by:
>
> 318af7b80b6a ("Revert "kbuild: use -flive-patching when CONFIG_LIVEPATCH is enabled"")
>
> but that was reportedly for gcc.
>
> Lemme Cc the people of interest and leave the rest in here for
> reference. Note that CONFIG_LIVEPATCH is enabled in that .config.

If somebody can share the .o file, I can take a look.

--
Josh