Re: [OE-core] [PATCH v7 01/14] linux-yocto: conditionally add clang/rust/bindgen-cli-native to DEPENDS

Harish Sadineni
2026-03-10T13:30:48Z

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On 3/10/2026 6:14 PM, Bruce Ashfield wrote:
> **
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> On Tue, Mar 10, 2026 at 6:58 AM Harish Sadineni
> <Harish.Sadineni@windriver.com> wrote:
>
>
> On 3/10/2026 12:50 AM, Richard Purdie wrote:
> > CAUTION: This email comes from a non Wind River email account!
> > Do not click links or open attachments unless you recognize the
> sender and know the content is safe.
> >
> > On Mon, 2026-03-09 at 14:01 -0400, Bruce Ashfield wrote:
> >>
> >>
> >> On Mon, Mar 9, 2026 at 12:54 PM Harish Sadineni
> >> <Harish.Sadineni@windriver.com> wrote:
> >>>
> >>>
> >>>
> >>>
> >>> On 3/9/2026 9:59 PM, Bruce Ashfield wrote:
> >>>
> >>>
> >>>> CAUTION: This email comes from a non Wind River email account!
> >>>>   Do not click links or open attachments unless you recognize the
> >>>> sender and know the content is safe.
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> On Mon, Mar 9, 2026 at 12:10 PM Harish Sadineni
> >>>> <Harish.Sadineni@windriver.com> wrote:
> >>>>
> >>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> On 3/9/2026 4:56 PM, Richard Purdie wrote:
> >>>>>
> >>>>>
> >>>>>> CAUTION: This email comes from a non Wind River email
> >>>>>> account!
> >>>>>> Do not click links or open attachments unless you recognize
> >>>>>> the sender and know the content is safe.
> >>>>>>
> >>>>>> On Wed, 2026-03-04 at 09:43 -0800, Sadineni, Harish via
> >>>>>> lists.openembedded.org
> <https://urldefense.com/v3/__http://lists.openembedded.org__;!!AjveYdw8EvQ!ekkiIdFR1oUUFgkUmXVgRrlc4N10osQLVSoHUP7tqKnyuU2FDh5UdcpyUkPIW6qIyPNmuAqUaeJv3wtCoY4XeJd8am36JgQ$>
> wrote:
> >>>>>>
> >>>>>>> From: Harish Sadineni <Harish.Sadineni@windriver.com>
> >>>>>>>
> >>>>>>> Conditionally add 'clang-native', 'rust-native' and
> >>>>>>> 'bindgen-cli-native' to 'DEPENDS'
> >>>>>>> when Kernel Rust Support is enabled.
> >>>>>>>
> >>>>>>> These tools are required for building Rust-enabled kernels
> >>>>>>> and for
> >>>>>>> generating Rust FFI bindings via bindgen during the kernel
> >>>>>>> build.
> >>>>>>>
> >>>>>>> This ensures the additional dependencies are only pulled in
> >>>>>>> when
> >>>>>>> Rust support is explicitly enabled, avoiding unnecessary
> >>>>>>> native
> >>>>>>> dependencies for non-Rust kernel builds.
> >>>>>>>
> >>>>>>> Signed-off-by: Harish Sadineni
> >>>>>>> <Harish.Sadineni@windriver.com>
> >>>>>>> ---
> >>>>>>>   meta/recipes-kernel/linux/linux-yocto.inc
> <https://urldefense.com/v3/__http://linux-yocto.inc__;!!AjveYdw8EvQ!ekkiIdFR1oUUFgkUmXVgRrlc4N10osQLVSoHUP7tqKnyuU2FDh5UdcpyUkPIW6qIyPNmuAqUaeJv3wtCoY4XeJd8KLPsVX0$>
> | 3 +++
> >>>>>>>   1 file changed, 3 insertions(+)
> >>>>>>>
> >>>>>>> diff --git a/meta/recipes-kernel/linux/linux-yocto.inc
> <https://urldefense.com/v3/__http://linux-yocto.inc__;!!AjveYdw8EvQ!ekkiIdFR1oUUFgkUmXVgRrlc4N10osQLVSoHUP7tqKnyuU2FDh5UdcpyUkPIW6qIyPNmuAqUaeJv3wtCoY4XeJd8KLPsVX0$>
> >>>>>>> b/meta/recipes-kernel/linux/linux-yocto.inc
> <https://urldefense.com/v3/__http://linux-yocto.inc__;!!AjveYdw8EvQ!ekkiIdFR1oUUFgkUmXVgRrlc4N10osQLVSoHUP7tqKnyuU2FDh5UdcpyUkPIW6qIyPNmuAqUaeJv3wtCoY4XeJd8KLPsVX0$>
> >>>>>>> index 4d0a726bb6..b7961bbcdf 100644
> >>>>>>> --- a/meta/recipes-kernel/linux/linux-yocto.inc
> <https://urldefense.com/v3/__http://linux-yocto.inc__;!!AjveYdw8EvQ!ekkiIdFR1oUUFgkUmXVgRrlc4N10osQLVSoHUP7tqKnyuU2FDh5UdcpyUkPIW6qIyPNmuAqUaeJv3wtCoY4XeJd8KLPsVX0$>
> >>>>>>> +++ b/meta/recipes-kernel/linux/linux-yocto.inc
> <https://urldefense.com/v3/__http://linux-yocto.inc__;!!AjveYdw8EvQ!ekkiIdFR1oUUFgkUmXVgRrlc4N10osQLVSoHUP7tqKnyuU2FDh5UdcpyUkPIW6qIyPNmuAqUaeJv3wtCoY4XeJd8KLPsVX0$>
> >>>>>>> @@ -76,11 +76,14 @@ do_install:append(){
> >>>>>>>  KERNEL_FEATURES:append:qemuall = " features/kernel-
> >>>>>>> sample/kernel-sample.scc"
> >>>>>>>
> >>>>>>>   KERNEL_DEBUG ?= ""
> >>>>>>> +KERNEL_RUST_SUPPORT ?= ""
> >>>>>>>   # These used to be version specific, but are now common
> >>>>>>> dependencies.  New
> >>>>>>>   # tools / dependencies will continue to be added in
> >>>>>>> version specific recipes.
> >>>>>>>   DEPENDS += '${@bb.utils.contains_any("ARCH", [ "x86",
> >>>>>>> "arm64", "powerpc" ], "elfutils-native", "", d)}'
> >>>>>>>   DEPENDS += "openssl-native util-linux-native"
> >>>>>>>   DEPENDS += "gmp-native libmpc-native"
> >>>>>>> +RUST_KERNEL_DEPENDS ?=
> >>>>>>> "${@bb.utils.contains('KERNEL_RUST_SUPPORT', 'True',
> >>>>>>> 'clang-native rust-native bindgen-cli-native', '', d)}"
> >>>>>>> +DEPENDS += "${RUST_KERNEL_DEPENDS}"
> >>>>>>>
> >>>>>>>   # Some options depend on CONFIG_PAHOLE_VERSION, so need to
> >>>>>>> make pahole-native available before do_kernel_configme
> >>>>>>>   do_kernel_configme[depends] +=
> >>>>>>> '${@bb.utils.contains("KERNEL_DEBUG", "True", "pahole-
> >>>>>>> native:do_populate_sysroot", "", d)}'
> >>>>>>>
> >>>>>> I thought we were going to try and use KERNEL_FEATURES for
> >>>>>> this?
> >>>>>>
> >>>>>   Hi Richard,
> >>>>>
> >>>>>   I have tried this but i got circular dependency error with
> >>>>> KERNEL_FEATURES. So, I opted using variable
> >>>>> KERNEL_RUST_SUPPORT.
> >>>>>
> >>>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> I'm curious about that. Can you share the details ? (diff and the
> >>>> bitbake error)
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>   As discussed previously, I attempted to use the following in
> >>> meta/recipes-kernel/linux/linux-yocto_6.18.bb
> <https://urldefense.com/v3/__http://linux-yocto_6.18.bb__;!!AjveYdw8EvQ!ekkiIdFR1oUUFgkUmXVgRrlc4N10osQLVSoHUP7tqKnyuU2FDh5UdcpyUkPIW6qIyPNmuAqUaeJv3wtCoY4XeJd8cBMffSY$>:
> >>>
> >>>   KERNEL_FEATURES:append = "
> ${@bb.utils.contains('KERNEL_FEATURES',
> >>> 'rust-kernel', ' features/kernel-rust/kernel-rust.scc', '', d)}"
> >>>
> >>>   This resulted in a BitBake variable dependency chain
> failure. The
> >>> issue occurs because the expression is trying to read
> >>> KERNEL_FEATURES
> >>>   while simultaneously modifying KERNEL_FEATURES, which creates a
> >>> circular dependency.
> >>>
> >>
> >> Yes, that's clearly not going to work, but that wouldn't have been
> >> the suggestion.
> >>
> >> Wasn't Richard asking about setting the RUST_KERNEL_DEPENDS
> based on
> >> the KERNEL_FEATURES containing rust.scc ?
> We understood like Richard suggestion is to use KERNEL_FEATURES
> everywhere instead of KERNEL_RUST_SUPPORT variable.
>
> We can use the KERNEL_RUST_SUPPORT variable to append rust.scc to
> KERNEL_FEATURES and then we could make other checks depends on
> KERNEL_FEATURES.
> But as the other recipes (make-mod-scripts, kernel-devsrc,
> module-rust.bbclass) do not know about KERNEL_FEATURES, so again
> we've
> to depend on KERNEL_RUST_SUPPORT Variable.
>
>
> I'm curious as to what you think is different about KERNEL_RUST_SUPPORT
> and KERNEL_FEATURES as variables ?
There is no difference i guess.
>
> They are both defined in the kernel recipe namespace, so any
> limitations about
> the visibility of one, is true about the other.

We will set KERNEL_RUST_SUPPORT = "true" in local.conf, so it is
globally visible.
In contrast, KERNEL_FEATURES is conditionally set based on
KERNEL_RUST_SUPPORT inside the kernel recipe,
meaning its value is only determined at the recipe level and not
accessible elsewhere.

Thanks,
Harish
>
> or am I missing something ?
>
> Bruce
>
>
> So, for consistency we used everywhere KERNEL_RUST_SUPPORT.
>
> Is this implementation ok or we should switch to use -
> KERNEL_FEATURES in kernel recipes and
> KERNEL_RUST_SUPPORT in other recipes.
>
> Thanks,
> Harish
> > Yes, along with maybe with a tweak to the KERNEL_FEATURES code which
> > could expand " rust " or maybe " kernel-rust "in KERNEL_FEATURES
> into
> > "features/kernel-rust/kernel-rust.scc" too just so there was a nice
> > short cut for it?
> >
> > Cheers,
> >
> > Richard
> >
> >
> >
>
>
>
> --
> - Thou shalt not follow the NULL pointer, for chaos and madness await
> thee at its end
> - "Use the force Harry" - Gandalf, Star Trek II
>

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