Re: [PATCH 1/2] scsi: bfa: fix function pointer type mismatch for hcb_qe->cbfn

Kees Cook
2023-06-21T18:33:33Z

On Fri, Jun 16, 2023 at 11:22:09AM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> Some callback functions used here take a boolean argument, others
> take a status argument. This breaks KCFI type checking, so clang
> now warns about the function pointer cast:
>
> drivers/scsi/bfa/bfad_bsg.c:2138:29: error: cast from 'void (*)(void *, enum bfa_status)' to 'bfa_cb_cbfn_t' (aka 'void (*)(void *, enum bfa_boolean)') converts to incompatible function type [-Werror,-Wcast-function-type-strict]
>
> Assuming the code is actually correct here and the callers always match
> the argument types of the callee, rework this to replace the explicit
> cast with a union of the two pointer types. This does not change the
> behavior of the code, so if something is actually broken here, a larger
> rework may be necessary.
>
> Fixes: 37ea0558b87ab ("[SCSI] bfa: Added support to collect and reset fcport stats")
> Fixes: 3ec4f2c8bff25 ("[SCSI] bfa: Added support to configure QOS and collect stats.")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Kees Cook <keescook@chromium.org>

--
Kees Cook