From: "Kumar Kartikeya Dwivedi" <memxor@gmail.com>
To: "Eduard Zingerman" <eddyz87@gmail.com>,
"Xu Kuohai" <xukuohai@huaweicloud.com>, <bpf@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Cc: "Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Emil Tsalapatis" <emil@etsalapatis.com>,
"Yonghong Song" <yonghong.song@linux.dev>,
"Anton Protopopov" <a.s.protopopov@gmail.com>
Subject: Re: [PATCH bpf-next v2 1/2] bpf: Eliminate dup/restore of insn_aux_data
Date: Thu, 13 Aug 2026 04:37:43 +0200 [thread overview]
Message-ID: <DKNGTPM2RNL9.2E66H1VIT9RW9@gmail.com> (raw)
In-Reply-To: <96eceba605b2cb7e93b3e33abf545a02c4eeb1cd.camel@gmail.com>
On Mon Aug 10, 2026 at 11:17 PM CEST, Eduard Zingerman wrote:
> On Tue, 2026-07-28 at 20:25 +0000, Xu Kuohai wrote:
>> From: Xu Kuohai <xukuohai@huawei.com>
>>
>> The dup/restore of insn_aux_data was introduced to resolve the
>> inconsistency between insnsi and insn_aux_data arrays, which occurs
>> on the failure path where insnsi was rolled back to the original
>> state before constants blinding, while insn_aux_data was not.
>>
>> After JIT failure, there is only one user, bpf_clear_insn_aux_data(),
>> that requires insnsi and insn_aux_data to be synchronized. It accesses
>> both insnsi and insn_aux_data using the same array size and index.
>>
>> However, the access to insnsi in bpf_clear_insn_aux_data() is not
>> necessary. It is checked to skip the second slot of an ldimm64 instruction,
>> whose jt is never set and can be absorbed into the jt check itself.
>>
>> So remove the access to insnsi from bpf_clear_insn_aux_data(), and add a
>> specific length field for insn_aux_data to allow it to have a different
>> length from the insnsi array. Then remove dup/restore of insn_aux_data.
>>
>> Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
>> ---
>
> Hi Xu, sorry for the delayed response, the patch lgtm.
>
> Acked-by: Eduard Zingerman <eddyz87@gmail.com>
>
> ...
I applied this one for now, thanks.
next prev parent reply other threads:[~2026-08-13 2:37 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-28 20:25 [PATCH bpf-next v2 0/2] bpf: Eliminate unnecessary clone/restore due to constants blinding Xu Kuohai
2026-07-28 20:25 ` [PATCH bpf-next v2 1/2] bpf: Eliminate dup/restore of insn_aux_data Xu Kuohai
2026-08-10 21:17 ` Eduard Zingerman
2026-08-13 2:37 ` Kumar Kartikeya Dwivedi [this message]
2026-07-28 20:25 ` [PATCH bpf-next v2 2/2] bpf: Remove unnecessary dup/restore subprog_starts and prog clone Xu Kuohai
2026-08-10 21:27 ` Eduard Zingerman
2026-08-11 13:00 ` Xu Kuohai
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