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Date: Sun, 8 Sep 2024 20:48:40 +0100
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Subject: Re: [PATCH] bpftool: Fix undefined behavior caused by shifting into
 the sign bit
To: Kuan-Wei Chiu <visitorckw@gmail.com>
Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
 martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org,
 yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org,
 sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org,
 jserv@ccns.ncku.edu.tw, bpf@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20240908140009.3149781-1-visitorckw@gmail.com>
From: Quentin Monnet <qmo@kernel.org>
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On 08/09/2024 15:00, Kuan-Wei Chiu wrote:
> Replace shifts of '1' with '1U' in bitwise operations within
> __show_dev_tc_bpf() to prevent undefined behavior caused by shifting
> into the sign bit of a signed integer. By using '1U', the operations
> are explicitly performed on unsigned integers, avoiding potential
> integer overflow or sign-related issues.
> 
> Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>


Looks good, thank you.

Acked-by: Quentin Monnet <qmo@kernel.org>

How did you find these?