From: Martin KaFai Lau <martin.lau@linux.dev>
To: Sami Tolvanen <samitolvanen@google.com>
Cc: Vadim Fedorenko <vadim.fedorenko@linux.dev>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Eduard Zingerman <eddyz87@gmail.com>, Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@fomichev.me>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>, Jamal Hadi Salim <jhs@mojatatu.com>,
Cong Wang <xiyou.wangcong@gmail.com>,
Jiri Pirko <jiri@resnulli.us>, Viktor Malik <vmalik@redhat.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
bpf@vger.kernel.org
Subject: Re: [PATCH bpf-next v5 0/4] Use correct destructor kfunc types
Date: Mon, 12 Jan 2026 12:33:15 -0800 [thread overview]
Message-ID: <a71a2980-9814-4f94-875b-cd6da6822a31@linux.dev> (raw)
In-Reply-To: <20260110082548.113748-6-samitolvanen@google.com>
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@kernel.org>
next prev parent reply other threads:[~2026-01-12 20:33 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-10 8:25 [PATCH bpf-next v5 0/4] Use correct destructor kfunc types Sami Tolvanen
2026-01-10 8:25 ` [PATCH bpf-next v5 1/4] bpf: crypto: Use the correct destructor kfunc type Sami Tolvanen
2026-01-10 18:49 ` kernel test robot
2026-01-10 8:25 ` [PATCH bpf-next v5 2/4] bpf: net_sched: " Sami Tolvanen
2026-01-10 8:25 ` [PATCH bpf-next v5 3/4] selftests/bpf: " Sami Tolvanen
2026-01-10 8:25 ` [PATCH bpf-next v5 4/4] bpf, btf: Enforce destructor kfunc type with CFI Sami Tolvanen
2026-01-12 20:33 ` Martin KaFai Lau [this message]
2026-01-13 3:00 ` [PATCH bpf-next v5 0/4] Use correct destructor kfunc types patchwork-bot+netdevbpf
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