linux-kernel - Re: [PATCH 1/5] fs/filesystems: Fix potential unsigned integer underflow in fs

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Message-ID: <a9bea6ae-27b1-468d-b895-f65189658abe@icloud.com>
Date: Sat, 12 Apr 2025 00:06:38 +0800
From: Zijun Hu <zijun_hu@...oud.com>
To: David Howells <dhowells@...hat.com>
Cc: Alexander Viro <viro@...iv.linux.org.uk>,
 Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>,
 linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
 Zijun Hu <quic_zijuhu@...cinc.com>
Subject: Re: [PATCH 1/5] fs/filesystems: Fix potential unsigned integer
 underflow in fs_name()

On 2025/4/11 23:34, David Howells wrote:
>> Fix by breaking the for loop when '@...ex == 0' which is also more proper
>> than '@...ex <= 0' for unsigned integer comparison.
> There isn't really a risk.  The list walked by "tmp" and the checks that this
> is or is not NULL will prevent a problem.
> 

no fixes tag is added and just improve code logic a bit since there is
no reason to continue the loop when @index reach 0.

> I also feel that breaking out of the loop with "<= 0" - even if the variable
> is unsigned - is safer, on the off chance that someone in the future changes
> the signedness of the variable.

for parameter @index representing filesystem index. unsigned integer
type may be better than signed.