From: Leon Hwang <leon.hwang@linux.dev>
To: Masoud Aghasi <maghasi@disroot.org>, bpf@vger.kernel.org
Cc: andrii@kernel.org, eddyz87@gmail.com, ast@kernel.org,
daniel@iogearbox.net, memxor@gmail.com, martin.lau@linux.dev,
song@kernel.org, yonghong.song@linux.dev, jolsa@kernel.org,
emil@etsalapatis.com, ihor.solodrai@linux.dev,
john.fastabend@gmail.com
Subject: Re: [PATCH bpf v6 1/3] bpf: Fix incorrect handling of user flags in bpf_percpu_array_update
Date: Thu, 8 Oct 2026 21:27:09 +0800 [thread overview]
Message-ID: <3e620809-3049-49db-bdcd-e451b9264100@linux.dev> (raw)
In-Reply-To: <20261008120734.1565972-2-maghasi@disroot.org>
On 2026/10/8 20:07, Masoud Aghasi wrote:
> For BPF_MAP_TYPE_PERCPU_ARRAY map, bpf_percpu_array_update()
> is not considering the possibility of a combination of
> (BPF_NOEXIST, BPF_EXIST) flags with (BPF_F_CPU, BPF_F_ALL_CPUS) flags.
> This causes the (BPF_NOEXIST, BPF_EXIST) flags to lose their effect
> in some cases.
>
> For example, using the (BPF_F_ALL_CPUS | BPF_EXIST) flag combination
> with bpf_map_update_elem() results in an incorrect EINVAL error
> response, even though the flag combination is valid.
>
> This patch fixes the bug by adding proper flag validations and checks.
> Before this patch, bpf_percpu_array_update() rejected
> BPF_F_ALL_CPUS | BPF_EXIST and BPF_F_ALL_CPUS | BPF_NOEXIST with
> -EINVAL. Also the BPF_F_CPU | BPF_NOEXIST were accepted.
> After the patch BPF_F_ALL_CPUS | BPF_EXIST is accepted and
> BPF_F_ALL_CPUS | BPF_NOEXIST and BPF_F_CPU | BPF_NOEXIST
> result in -EEXIST.
>
> This patch also starts returning -EINVAL for (BPF_EXIST | BPF_NOEXIST),
> with or without BPF_F_CPU, which was previously accepted.
>
> Fixes: 8eb76cb03f0f ("bpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu_array maps")
> Signed-off-by: Masoud Aghasi <maghasi@disroot.org>
Should carry my Acked-by in v5.
Acked-by: Leon Hwang <leon.hwang@linux.dev>
> [...]
next prev parent reply other threads:[~2026-10-08 13:27 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-08 12:07 [PATCH bpf v6 0/3] bpf: Fix incorrect handling of user flags by percpu map updates Masoud Aghasi
2026-10-08 12:07 ` [PATCH bpf v6 1/3] bpf: Fix incorrect handling of user flags in bpf_percpu_array_update Masoud Aghasi
2026-10-08 13:27 ` Leon Hwang [this message]
2026-10-08 12:07 ` [PATCH bpf v6 2/3] bpf: Fix incorrect handling of user flags by percpu hash map updates Masoud Aghasi
2026-10-08 13:27 ` Leon Hwang
2026-10-08 12:07 ` [PATCH bpf v6 3/3] selftests/bpf: add tests for percpu map flags combination Masoud Aghasi
2026-10-08 13:28 ` Leon Hwang
2026-10-08 15:58 ` Masoud Aghasi
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