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

Harish Sadineni
2026-03-09T16:54:14Z

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On 3/9/2026 9:59 PM, Bruce Ashfield wrote:
> **
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> 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 vialists.openembedded.org <https://urldefense.com/v3/__http://lists.openembedded.org__;!!AjveYdw8EvQ!cWPq0za66UhcuPm1JB9FSYJ5JMWWpL_480vZLcrK0BTZbuoPaFvjdJly1r2bF4S-jo8X5LrrrXkmL3xU90Zr5Er_U2VxaLk$> wrote:
>>> From: Harish Sadineni<Harish.Sadineni@windriver.com> <mailto:Harish.Sadineni@windriver.com>
>>>
>>> Conditionally add 'clang-native', 'rust-native' and 'bindgen-cli-native' to 'DEPENDS'
>>> when Kernel Rust Support is enabled.
>>>
>>> These tools are required for building Rust-enabled kernels and for
>>> generating Rust FFI bindings via bindgen during the kernel build.
>>>
>>> This ensures the additional dependencies are only pulled in when
>>> Rust support is explicitly enabled, avoiding unnecessary native
>>> dependencies for non-Rust kernel builds.
>>>
>>> Signed-off-by: Harish Sadineni<Harish.Sadineni@windriver.com> <mailto:Harish.Sadineni@windriver.com>
>>> ---
>>> meta/recipes-kernel/linux/linux-yocto.inc <https://urldefense.com/v3/__http://linux-yocto.inc__;!!AjveYdw8EvQ!cWPq0za66UhcuPm1JB9FSYJ5JMWWpL_480vZLcrK0BTZbuoPaFvjdJly1r2bF4S-jo8X5LrrrXkmL3xU90Zr5Er_ybuc9RA$> | 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!cWPq0za66UhcuPm1JB9FSYJ5JMWWpL_480vZLcrK0BTZbuoPaFvjdJly1r2bF4S-jo8X5LrrrXkmL3xU90Zr5Er_ybuc9RA$> b/meta/recipes-kernel/linux/linux-yocto.inc <https://urldefense.com/v3/__http://linux-yocto.inc__;!!AjveYdw8EvQ!cWPq0za66UhcuPm1JB9FSYJ5JMWWpL_480vZLcrK0BTZbuoPaFvjdJly1r2bF4S-jo8X5LrrrXkmL3xU90Zr5Er_ybuc9RA$>
>>> index 4d0a726bb6..b7961bbcdf 100644
>>> --- a/meta/recipes-kernel/linux/linux-yocto.inc <https://urldefense.com/v3/__http://linux-yocto.inc__;!!AjveYdw8EvQ!cWPq0za66UhcuPm1JB9FSYJ5JMWWpL_480vZLcrK0BTZbuoPaFvjdJly1r2bF4S-jo8X5LrrrXkmL3xU90Zr5Er_ybuc9RA$>
>>> +++ b/meta/recipes-kernel/linux/linux-yocto.inc <https://urldefense.com/v3/__http://linux-yocto.inc__;!!AjveYdw8EvQ!cWPq0za66UhcuPm1JB9FSYJ5JMWWpL_480vZLcrK0BTZbuoPaFvjdJly1r2bF4S-jo8X5LrrrXkmL3xU90Zr5Er_ybuc9RA$>
>>> @@ -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)}" <mailto:$%7B@bb.utils.contains('KERNEL_RUST_SUPPORT','True','clang-nativerust-nativebindgen-cli-native','',d)%7D>
>>> +DEPENDS += "${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:

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.

example:
The variable dependency chain for the failure is: KERNEL_FEATURES ->
KERNEL_FEATURES -> KERNEL_FEATURES -> KERNEL_FEATURES...

Thanks,
Harish
>
> Bruce
>
>> The implementation of KERNEL_RUST_SUPPORT is problematic as it only
>> works for the value of "True", not "true", or "1" or 1 or any other
>> thing people might dream up. "Contains" isn't really an appropriate
>> mechanism for a boolean either.
>>
>> You can use bb.utils.to_boolean() as a way to better obtain a boolean
>> value from a random variable.
> Understood, Earlier i took reference from the code that already
> present in that file.
> I have updated the code we will send v8.
>
> Thanks,
> Harish
>> 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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