Re: [PATCH bpf-next v6 8/9] selftests/bpf: Add tracing prog private stack tests

[Jiri Olsa <olsajiri@gmail.com>]

On Mon, Oct 21, 2024 at 09:19:57AM -0700, Yonghong Song wrote:

SNIP

> > > In my system, the gcc version is 13.1. So there is no need to explicitly add
> > > CONFIG_X86_KERNEL_IBT to the selftests/bpf/config.x86_64 file.
> > I had to enable it manualy for gcc 13.3.1
> 
> IIUC, the ci config is generated based on config + config.x86_64 + config.vm
> in tools/testing/selftests/bpf directory.
> 
> In my case .config is generated from config + config.x86_64 + config.vm
> With my local gcc 11.5, I did
>    make olddefconfig
> and I see CONFIG_X86_KERNEL_IBT=y is set.
> 
> Maybe your base config is a little bit different from what ci used.
> My local config is based on ci config + some more e.g. enabling KASAN etc.
> 
> Could you debug a little more on why CONFIG_X86_KERNEL_IBT not enabled
> by default in your case? For

ok, I think I disabled that manually

> 
> config X86_KERNEL_IBT
>         prompt "Indirect Branch Tracking"
>         def_bool y
>         depends on X86_64 && CC_HAS_IBT && HAVE_OBJTOOL
>         # https://github.com/llvm/llvm-project/commit/9d7001eba9c4cb311e03cd8cdc231f9e579f2d0f
>         depends on !LD_IS_LLD || LLD_VERSION >= 140000
>         select OBJTOOL
>         select X86_CET
> 
> default is 'y' so if all dependencies are met, CONFIG_X86_KERNEL_IBT
> is supposed to be on by default.

ah right, that should work then.. thanks for the details

jirka