linux-kernel - Re: linux-next: Tree for Jul 10 (arch/s390/kernel/machine_kexec

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Date:   Tue, 11 Jul 2023 13:49:42 -0500
From:   Eric DeVolder <eric.devolder@...cle.com>
To:     Randy Dunlap <rdunlap@...radead.org>,
        Stephen Rothwell <sfr@...b.auug.org.au>,
        Linux Next Mailing List <linux-next@...r.kernel.org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: linux-next: Tree for Jul 10
 (arch/s390/kernel/machine_kexec_file.c)



On 7/10/23 17:15, Randy Dunlap wrote:
> 
> 
> On 7/10/23 14:27, Eric DeVolder wrote:
>>
>>
>> On 7/10/23 15:23, Eric DeVolder wrote:
>>>
>>>
>>> On 7/10/23 15:11, Randy Dunlap wrote:
>>>>
>>>>
>>>> On 7/9/23 18:38, Stephen Rothwell wrote:
>>>>> Hi all,
>>>>>
>>>>> Changes since 20230707:
>>>>>
>>>>
>>>> on s390:
>>>>
>>>> ../arch/s390/kernel/machine_kexec_file.c: In function 's390_verify_sig':
>>>> ../arch/s390/kernel/machine_kexec_file.c:69:15: error: implicit declaration of function 'verify_pkcs7_signature' [-Werror=implicit-function-declaration]
>>>>      69 |         ret = verify_pkcs7_signature(kernel, kernel_len,
>>>>         |               ^~~~~~~~~~~~~~~~~~~~~~
>>>> cc1: some warnings being treated as errors
>>>>
>>>>
>>>> Full randconfig file is attached.
>>>>
>>>
>>> Randy,
>>> Thanks for this. This appears to be randconfig testing against linux-next.
>>> As of right now, linux-next does not contain the v5 that I posted friday.
>>> The v5 posted friday was picked up by Andrew and over the weekend no fails
>>> discovered, and the series currently sits in mm-everything branch. So hopefully
>>> it will appear soon in linux-next!
>>>
>>> Let me know if I misunderstand the situation.
>>> Thanks!
>>> eric
>>
>> Well the root cause is a missing SYSTEM_DATA_VERIFICATION. This was discussed
>> through MODULE_SIG_FORMAT thread. I don't think v5 changed anything with
>> respect to this issue, so it will likely reveal itself again.
>>
>> Since it was agreed to drop MODULE_SIG_FORMAT, and my attempt to select
>> SYSTEM_DATA_VERIFICATION results in same circular dependency as with
>> MODULE_SIG_FORMAT, I'm unsure how to proceed.
>>
>> The arch/s390/Kconfig S390 option has a 'select KEXEC' (but not KEXEC_FILE),
>> maybe we consider adding a 'select SYSTEM_DATA_VERIFICATION' as well?
> 
> Sure, since some other configs select it also.
> And as long as it doesn't cause a circular dependency problem.
> 
> thanks.

Randy, all,
I did the following for s390 and it "works", but I don't think we can use it.

Changed:

config ARCH_SUPPORTS_KEXEC_FILE
     def_bool CRYPTO && CRYPTO_SHA256 && CRYPTO_SHA256_S390

to:

config ARCH_SELECTS_KEXEC_FILE
         def_bool y
         depends on KEXEC_FILE
         select CRYPTO
         select CRYPTO_SHA256
         select CRYPTO_SHA256_S390
         select SYSTEM_DATA_VERIFICATION

and this essentially passes my regression but for the following:

FAIL olddefconfig arch/s390/configs/defconfig
LHSB {'CONFIG_CRYPTO_SHA256_S390': 'm'}
RHSB {'CONFIG_CRYPTO_SHA256_S390': 'y'}

which simply means that the CRYPTO_SHA256_S390 is always built-in, whereas previously
it could be a module. This happens because 'select' is always =y; overwrites if
previously =m, as was the case with this particular config file.

I still don't know how to close this gap. Today I see linux-next has v5 in it.
eric