Re: [PATCH v2 1/2] bpf: Fix incorrect handling of user flags by percpu map updates

[Leon Hwang <leon.hwang@linux.dev>]

Hi Masoud,

Thanks for the fix.

Pls add target tree in subject, like
[PATCH bpf v3 ...] bpf: ...

On 2026/9/30 21:57, Masoud Aghasi wrote:
> For BPF_MAP_TYPE_PERCPU_HASH map, htab_map_check_update_flags() and
> check_flags() are 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.
> 
> For example, when using (BPF_F_CPU | BPF_EXIST) flag combination
> with bpf_map_update_elem() on a BPF_MAP_TYPE_PERCPU_HASH map, the
> BPF_EXIST flag does not prevent new insertions as expected.
> 
> Also for BPF_MAP_TYPE_PERCPU_ARRAY map, 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.
> 
> Fixes: c6936161fd55 ("bpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu_hash and lru_percpu_hash maps")
> Fixes: 8eb76cb03f0f ("bpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu_array maps")

I'd like to split this patch into two patches: one for lru_/percpu_hash
maps, another one for percpu_array maps.

Is there similar issue to percpu_cgroup_storage maps?

Thanks,
Leon

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