Re: [PATCH bpf-next v5 0/4] Use correct destructor kfunc types

[Martin KaFai Lau]

On 1/10/26 12:25 AM, Sami Tolvanen wrote:
> Hi folks,
>
> While running BPF self-tests with CONFIG_CFI (Control Flow
> Integrity) enabled, I ran into a couple of failures in
> bpf_obj_free_fields() caused by type mismatches between the
> btf_dtor_kfunc_t function pointer type and the registered
> destructor functions.
>
> It looks like we can't change the argument type for these
> functions to match btf_dtor_kfunc_t because the verifier doesn't
> like void pointer arguments for functions used in BPF programs,
> so this series fixes the issue by adding stubs with correct types
> to use as destructors for each instance of this I found in the
> kernel tree.
>
> The last patch changes btf_check_dtor_kfuncs() to enforce the
> function type when CFI is enabled, so we don't end up registering
> destructors that panic the kernel.

Acked-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>