Re: [PATCH v2] tracing: Make is_signed_type() compatible with sparse

[Linus Torvalds]

On Wed, 2 Sept 2026 at 13:50, David Laight <david.laight.linux@xxxxxxxxx> wrote:
>
> Actually it wouldn't really to any harm to nuke the __bitwise on those fields.
> It seems to be an attempt to generate strongly typed integers, but it doesn't
> stop you mixing up the values between the fields - there is only one kind
> of __bitwise.

Nope - there are multipel __bitwise.

Each typedef creates a new type. Try this:

        typedef int __attribute__((bitwise)) a_t;
        typedef int __attribute__((bitwise)) b_t;

        static a_t a;
        static b_t b;

        void test(void)
        {
                a = b;
        }

and notice how it warns:

    t.c:9:19: warning: incorrect type in assignment (different base types)
    t.c:9:19:    expected restricted a_t static [signed] [toplevel] [usertype] a
    t.c:9:19:    got restricted b_t static [signed] [toplevel] [usertype] b

because the types of 'a' and 'b' are not the same.

               Linus