Re: [PATCH 3/4] livepatch/shadow: Introduce klp_shadow_type structure

[Josh Poimboeuf <jpoimboe@redhat.com>]

On Fri, Jul 01, 2022 at 04:48:16PM -0300, Marcos Paulo de Souza wrote:
> The shadow variable type will be used in klp_shadow_alloc/get/free
> functions instead of id/ctor/dtor parameters. As a result, all callers
> use the same callbacks consistently[*][**].
> 
> The structure will be used in the next patch that will manage the
> lifetime of shadow variables and execute garbage collection automatically.
> 
> [*] From the user POV, it might have been easier to pass $id instead
>     of pointer to struct klp_shadow_type.
> 
>     The problem is that each livepatch registers its own struct
>     klp_shadow_type and defines its own @ctor/@dtor callbacks. It would
>     be unclear what callback should be used. They should be compatible.
> 
>     This problem is gone when each livepatch explicitly uses its
>     own struct klp_shadow_type pointing to its own callbacks.
> 
> [**] test_klp_shadow_vars.c uses a custom @dtor to show that it was called.
>     The message must be disabled when called via klp_shadow_free_all()
>     because the ordering of freed variables is not well defined there.
>     It has to be done using another hack after switching to
>     klp_shadow_types.
> 
> Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
> Signed-off-by: Petr Mladek <pmladek@suse.com>

Invalid SOB chain, see

  Documentation/process/submitting-patches.rst

-- 
Josh