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Subject: Re: [PATCH 0/1] Add explicit error for missing CONFIG_ASN1
To:     James Bottomley <James.Bottomley@HansenPartnership.com>,
        linux-kbuild@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org,
        Masahiro Yamada <masahiroy@kernel.org>
References: <20200922155341.17906-1-James.Bottomley@HansenPartnership.com>
 <dfae4d4f-aa96-674d-93b1-d4c097e720e4@infradead.org>
 <260b4b85d714df822da259554ef8cc2873f3096f.camel@HansenPartnership.com>
From:   Randy Dunlap <rdunlap@infradead.org>
Message-ID: <36232f66-58b1-77a8-91a3-f9d3428fffb5@infradead.org>
Date:   Tue, 22 Sep 2020 12:38:27 -0700
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On 9/22/20 12:19 PM, James Bottomley wrote:
> On Tue, 2020-09-22 at 11:54 -0700, Randy Dunlap wrote:
>> On 9/22/20 8:53 AM, James Bottomley wrote:
>>> I recently ran into this as an error from 0day.  On x86 it's pretty
>>> much impossible to build a configuration where CONFIG_ASN1 isn't
>>> set, so you rarely notice a problem using the ASN.1 compiler
>>> because something else has selected it.  However, this compiler is
>>> never built if CONFIG_ASN1 isn't set and the error you get from
>>> kbuild is particularly unhelpful:
>>>
>>>    make[4]: *** No rule to make target 'security/keys/trusted-
>>> keys/tpm2key.asn1.o', needed by 'security/keys/trusted-keys/built-
>>> in.a'.
>>>    make[4]: *** [scripts/Makefile.build:283: security/keys/trusted-
>>> keys/trusted_tpm2.o] Error 1
>>>    make[4]: Target '__build' not remade because of errors.
>>>
>>> This patch changes the above error to the much easier to diagnose:
>>>
>>>    scripts/Makefile.build:387: *** CONFIG_ASN1 must be defined for
>>> the asn1_compiler.  Stop.
>>>    make[3]: *** [scripts/Makefile.build:505: security/keys/trusted-
>>> keys] Error 2
>>>
>>> James
>>>
>>> ---
>>>
>>> James Bottomley (1):
>>>   Makefile.build: Add an explicit error for missing ASN.1 compiler
>>>
>>>  scripts/Makefile.build | 5 +++++
>>>  1 file changed, 5 insertions(+)
>>
>> Is there a missing
>> 	select ASN1
>> somewhere?
> 
> You mean in the build used to produce the errors above?  Yes, so the
> patch is to make the problem more explicit.

I appreciate that the message can be improved, but it seems possible
that some Kconfig could also be improved.

-- 
~Randy