Re: [XEN PATCH v2 2/3] x86/uaccess: replace __{get,put}_user_bad() with STATIC_ASSERT_UNREACHABLE()

[Jan Beulich <jbeulich@xxxxxxxx>]

On 19.02.2024 21:43, Stefano Stabellini wrote:
> On Mon, 19 Feb 2024, Federico Serafini wrote:
>> On 15/02/24 11:32, Jan Beulich wrote:
>>> The important difference is: Here we're told that there was a use of
>>> __put_user_bad, which is easy to grep for, and thus see how the
>>> supplied function / file / line(?) relate to the ultimate problem.
>>>
>>> I'm afraid I'm meanwhile confused enough by the various replies
>>> containing results of experimentation that I can't really tell
>>> anymore what case is best. Hence I can only restate my expectation for
>>> an eventual v3: Diagnosing what the issue is, no matter whether the new
>>> macro is used in another macro or in an inline function, should not
>>> become meaningfully more difficult. In how far this is the case wants
>>> clarifying in the description of the change.
>>
>> I think the best thing at the moment is to deviate
>> __{get,put}_user_bad() for Rule 16.3.
>> I'll let maintainers further explore the possibility of having a
>> compile-time assertion based on the assembler error.
> 
> OK. I hope Jan is OK to deviate by in-code comment.

Hmm, the follow-on suggestion was to add break statements? Followed
by me asking whether adding noreturn to the decls wouldn't also help.
(Then again I was under the impression that there was more than just
the "missing" break statements which Misra thought was an issue here.)

Jan