From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Kohei Enju <enjuk@amazon.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-kselftest@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
Stanislav Fomichev <sdf@fomichev.me>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Eduard Zingerman <eddyz87@gmail.com>, Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
KP Singh <kpsingh@kernel.org>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>, Shuah Khan <shuah@kernel.org>,
kohei.enju@gmail.com, Kohei Enju <enjuk@amazon.com>
Subject: Re: [PATCH bpf-next v2 1/2] bpf: cpumap: propagate underlying error in cpu_map_update_elem()
Date: Mon, 08 Dec 2025 15:19:55 +0100 [thread overview]
Message-ID: <87o6o96ook.fsf@toke.dk> (raw)
In-Reply-To: <20251208131449.73036-2-enjuk@amazon.com>
Kohei Enju <enjuk@amazon.com> writes:
> After commit 9216477449f3 ("bpf: cpumap: Add the possibility to attach
> an eBPF program to cpumap"), __cpu_map_entry_alloc() may fail with
> errors other than -ENOMEM, such as -EBADF or -EINVAL.
>
> However, __cpu_map_entry_alloc() returns NULL on all failures, and
> cpu_map_update_elem() unconditionally converts this NULL into -ENOMEM.
> As a result, user space always receives -ENOMEM regardless of the actual
> underlying error.
>
> Examples of unexpected behavior:
> - Nonexistent fd : -ENOMEM (should be -EBADF)
> - Non-BPF fd : -ENOMEM (should be -EINVAL)
> - Bad attach type : -ENOMEM (should be -EINVAL)
>
> Change __cpu_map_entry_alloc() to return ERR_PTR(err) instead of NULL
> and have cpu_map_update_elem() propagate this error.
>
> Signed-off-by: Kohei Enju <enjuk@amazon.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
next prev parent reply other threads:[~2025-12-08 14:20 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-08 13:14 [PATCH bpf-next v2 0/2] bpf: cpumap: improve error propagation in cpu_map_update_elem() Kohei Enju
2025-12-08 13:14 ` [PATCH bpf-next v2 1/2] bpf: cpumap: propagate underlying error " Kohei Enju
2025-12-08 14:19 ` Toke Høiland-Jørgensen [this message]
2025-12-08 13:14 ` [PATCH bpf-next v2 2/2] selftests/bpf: add tests for attaching invalid fd Kohei Enju
2025-12-08 14:20 ` Toke Høiland-Jørgensen
2025-12-10 8:00 ` [PATCH bpf-next v2 0/2] bpf: cpumap: improve error propagation in cpu_map_update_elem() patchwork-bot+netdevbpf
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