linux-kernel - Re: [PATCH bpf] bpf/tests: Remove test for MOVSX32 with offset=32

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Message-ID: <ZVEkJ9waaH9X11GR@google.com>
Date:   Sun, 12 Nov 2023 11:14:47 -0800
From:   Stanislav Fomichev <sdf@...gle.com>
To:     Puranjay Mohan <puranjay12@...il.com>
Cc:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <martin.lau@...ux.dev>,
        Song Liu <song@...nel.org>,
        Yonghong Song <yonghong.song@...ux.dev>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>, Hao Luo <haoluo@...gle.com>,
        Jiri Olsa <jolsa@...nel.org>,
        "open list:BPF [GENERAL] (Safe Dynamic Programs and Tools)" 
        <bpf@...r.kernel.org>, open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH bpf] bpf/tests: Remove test for MOVSX32 with offset=32

On 11/10, Puranjay Mohan wrote:
> MOVSX32 only supports sign extending 8-bit and 16-bit operands into 32
> bit operands. The "ALU_MOVSX | BPF_W" test tries to sign extend a 32 bit
> operand into a 32 bit operand which is equivalent to a normal BPF_MOV.
> 
> Remove this test as it tries to run an invalid instruction.
> 
> Fixes: daabb2b098e0 ("bpf/tests: add tests for cpuv4 instructions")
> Signed-off-by: Puranjay Mohan <puranjay12@...il.com>
> Reported-by: kernel test robot <oliver.sang@...el.com>
> Closes: https://lore.kernel.org/oe-lkp/202310111838.46ff5b6a-oliver.sang@intel.com

Acked-by: Stanislav Fomichev <sdf@...gle.com>

(based on the fact that emit_movsx_reg doesn't handle 32 bit case under !is64)