Date:   Thu, 6 Jan 2022 16:01:20 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Jiasheng Jiang <jiasheng@iscas.ac.cn>
Cc:     jirislaby@kernel.org, linux-serial@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] tty/serial: Check for null pointer after calling
 devm_ioremap
Message-ID: <YdcEQPS30BHTPQJo@kroah.com>
References: <20220106090631.2714586-1-jiasheng@iscas.ac.cn>
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In-Reply-To: <20220106090631.2714586-1-jiasheng@iscas.ac.cn>
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On Thu, Jan 06, 2022 at 05:06:31PM +0800, Jiasheng Jiang wrote:
> As the possible failure of the allocation, the devm_ioremap() may return
> NULL pointer.

I do not understand this sentence.

> And the 'port->membase' will be directly used in mlb_usio_startup().

This does not make sense either.


> Therefore, in order to avoid the dereference of the NULL pointer, it
> should be better to add the sanity check.

What do you mean by "sanity check"?

confused,

greg k-h