Re: [PATCH v2] Fix initializing a static union variable

[Herbert Xu]

On Fri, Jun 21, 2024 at 02:18:19PM -0700, Yabin Cui wrote:
> saddr_wildcard is a static union variable initialized with {}.
> 
> Empty brace initialization of union types is unspecified prior to C23,
> and even in C23, it doesn't guarantee zero initialization of all fields
> (see sections 4.5 and 6.2 in
> https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2900.htm).

What about all the other places in the kernel that use the same
idiom? A grep shows that there are more than a hundred spots in
the kernel where {} is used to initialise a union.

$ git grep '=[[:blank:]]*{}' | grep union | wc -l
123
$

Also what if the union is embedded into a struct.  Does it get
initialised fully or not? If not then you've got over 5000 {}
initialisations to work through.

$ git grep '=[[:blank:]]*{}' | wc -l
5102
$

Cheers,
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
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