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From:   Li Zhong <floridsleeves@gmail.com>
Date:   Fri, 26 Aug 2022 01:27:19 -0700
Message-ID: <CAMEuxRpKqHHfT2J-6V1JqyWSMqS4uwCNiLMFLEoYkfpuTM8TuQ@mail.gmail.com>
Subject: Re: [PATCH v1] drivers/tty/serial: check the return value of uart_port_check()
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
        jirislaby@kernel.org
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On Mon, Aug 22, 2022 at 11:20 PM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Mon, Aug 22, 2022 at 10:57:39PM -0700, lily wrote:
> > uart_port_check() can return NULL pointer.
>
> It can?  How will that happen?
>
When state->uart_port is NULL, uart_port_check() will return a NULL pointer.
This actually is checked in other places like
drivers/tty/serial/serial_core.c:762.
> > Check its return value before dereference it.
>
> How do you trigger this issue, and how was this change you made tested?
>
I detect this issue with a static analysis tool, therefore not dynamically
triggered.
> thanks,
>
> greg k-h