From: Masoud Aghasi <maghasi@disroot.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: bpf <bpf@vger.kernel.org>, Andrii Nakryiko <andrii@kernel.org>,
Eduard <eddyz87@gmail.com>, Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
Jiri Olsa <jolsa@kernel.org>,
Emil Tsalapatis <emil@etsalapatis.com>,
Ihor Solodrai <ihor.solodrai@linux.dev>,
John Fastabend <john.fastabend@gmail.com>,
Brian Vazquez <brianvv@google.com>
Subject: Re: [PATCH v3] bpf: Fix u32 overflow issue in map batch operations
Date: Mon, 7 Sep 2026 00:34:45 +0100 [thread overview]
Message-ID: <da7d3192-a275-4d6a-bf9c-525bdbb6c9fa@disroot.org> (raw)
In-Reply-To: <CAADnVQLX5bjLTPm8Ch0wNuojHrKw6R5iJDBRsMJwrWMSupVwew@mail.gmail.com>
On 04/09/2026 05:45, Alexei Starovoitov wrote:
> On Thu, Sep 3, 2026 at 1:28 AM Masoud Aghasi <maghasi@disroot.org> wrote:
>>
>> Several map batch operation implementations such as
>> generic_map_lookup_batch() use calculations in the form of
>> "values + cp * map->value_size" to compute the desired userspace memory
>> address for reading or writing. This can overflow the u32 type
>> (the result of "cp * map->value_size") when the map size exceeds 4GB.
>>
>> generic_map_lookup_batch() may corrupt values for some keys in
>> userspace memory, and in some cases it mismatches values for some keys
>> while still reporting success.
>
> without selftest I have to assume that this is AI hallucination.
>
> pw-bot: cr
And here is the output of the same test after patching the kernel:
$ sudo ./test_progs -t map_batch_overflow
#212/1 map_batch_overflow/array_lookup:OK
#212/2 map_batch_overflow/array_lookup_4gb_plus:OK
#212/3 map_batch_overflow/array_update:OK
#212/4 map_batch_overflow/array_update_4gb_plus:OK
#212 map_batch_overflow:OK
Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED
Sorry for replying in multiple emails.
next prev parent reply other threads:[~2026-09-06 23:34 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-24 11:31 [PATCH] bpf: Fix u32 overflow issue in map batch operations Masoud Aghasi
2026-08-24 11:42 ` sashiko-bot
2026-08-25 10:21 ` Masoud Aghasi
2026-09-02 20:44 ` [PATCH v2] " Masoud Aghasi
2026-09-02 21:50 ` bot+bpf-ci
2026-09-03 8:27 ` [PATCH v3] " Masoud Aghasi
2026-09-03 8:45 ` sashiko-bot
2026-09-03 12:31 ` Masoud Aghasi
2026-09-04 4:45 ` Alexei Starovoitov
2026-09-04 13:19 ` Masoud Aghasi
2026-09-06 22:42 ` Masoud Aghasi
2026-09-06 23:34 ` Masoud Aghasi [this message]
2026-08-24 12:17 ` [PATCH] " bot+bpf-ci
2026-08-24 19:15 ` Masoud Aghasi
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