Re: [PATCH] scripts/gen-btf.sh: fix shebang for NixOS

[Ihor Solodrai <ihor.solodrai@linux.dev>]

On 1/20/26 8:52 PM, Alexei Starovoitov wrote:
> On Tue, Jan 20, 2026 at 8:50 PM Ihor Solodrai <ihor.solodrai@linux.dev> wrote:
>>
>>
>>
>> On 1/20/26 3:54 PM, Gary Guo wrote:
>>>> [...]
>>>>
>>>> So it's trivial to put $(CONFIG_SHELL) in front of it. But then it
>>>> must be migrated to #!/bin/sh, right?
>>>
>>> Documentation/kbuild/makefiles.rst says:
>>>
>>> Make rules may invoke scripts to build the kernel. The rules shall
>>> always provide the appropriate interpreter to execute the script. They
>>> shall not rely on the execute bits being set, and shall not invoke the
>>> script directly. For the convenience of manual script invocation, such
>>> as invoking ./scripts/checkpatch.pl, it is recommended to set execute
>>> bits on the scripts nonetheless.
>>>
>>> Kbuild provides variables $(CONFIG_SHELL), $(AWK), $(PERL),
>>> and $(PYTHON3) to refer to interpreters for the respective
>>> scripts.
>>>
>>> So I suppose it would need to migate to POSIX shell...
>>
>> That's my blunder then.
>>
>> I'll send a patch tomorrow to make gen-btf.sh runnable with /bin/sh
> 
> Isn't the current patch enough?
> -#!/bin/bash
> +#!/usr/bin/env bash
> 
> I don't think all kernel build scripts are pure 'sh'.

Well, if we want to follow the makefiles.rst (and Thomas')
recommendation, which is executing the script via $(CONFIG_SHELL),
then we have to migrate to #!/bin/sh, because that's the default.

This concerns only scripts in the kernel build pipeline AFAIU.

But you may be right that this is not a strict rule, idk.
It did come up quite late on the list.