[PATCH v2 0/5] vDSO: Use 32-bit CHECKFLAGS for compat vDSO

[Christophe Leroy (CS GROUP)]

Le 06/03/2026 à 14:08, Thomas Weißschuh a écrit :
> On Fri, Mar 06, 2026 at 11:43:24AM +0100, Christophe Leroy (CS GROUP) wrote:
>>
>>
>> Le 02/03/2026 à 08:58, Thomas Weißschuh a écrit :
>>> When building the compat vDSO the CHECKFLAGS from the 64-bit kernel
>>> are used. These are combined with the 32-bit CFLAGS. This confuses
>>> sparse, producing false-positive warnings or potentially missing
>>> real issues.
>>>
>>> Manually override the CHECKFLAGS for the compat vDSO with the correct
>>> 32-bit configuration.
>>>
>>> Not all architectures are supported, as many do not use sparse for their
>>> (compat) vDSO. These can be enabled later.
>>>
>>> Also add some checks to bitsperlong.h to detect such issues earlier.
>>>
>>> Based on tip/timers/vdso.
>>>
>>> Signed-off-by: Thomas Weißschuh <thomas.weissschuh at linutronix.de>
>>> ---
>>> Changes in v2:
>>> - Simplify __BITS_PER_LONG consistency checks
>>> - Fix an inconsistency in the powerpc audit code
>>
>> The powerpc audit code should be replaced by generic
>> AUDIT_ARCH_COMPAT_GENERIC, as there is no difference between them
>> apparently.
> 
> Agreed.
> 
>> A tentative was made in the past but was declined by audit maintainers
>> because we were not able to test it allthought the failure was the same
>> before and after the patch, see
>> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Flinuxppc%2Fissues%2Fissues%2F412&data=05%7C02%7Cchristophe.leroy%40csgroup.eu%7Cca6c85b42bd44c6a80c608de7b81819d%7C8b87af7d86474dc78df45f69a2011bb5%7C0%7C0%7C639083993321723266%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=VxTy22klpH9H8Altgcthr%2F%2ByUIL6q%2FbBkDV7FQS%2BljI%3D&reserved=0
> 
> On v7.0-rc1 the test failure of filter_exclude/test is gone.
> It also keeps working when applying your patch. Some other tests are
> broken, but it looks that is due to missing dependencies on Debian.
> So maybe it is time to resubmit your patch.
> 
> In any case, I don't really want to entangle my series with the switch
> to AUDIT_ARCH_COMPAT_GENERIC. My proposed cleanup does not make the code
> worse and if both patches are applied the conflict will be trivial to
> resolve.

I didn't mean to interfere with your patch, it is just that your patch 
reminded me that tentative.

Thanks for testing, I will consider re-posting my patch based on your test.

Christophe