Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230728122416.17782-1-lianglixuehao@126.com>
In-Reply-To: <20230728122416.17782-1-lianglixuehao@126.com>
From:   Joel Stanley <joel@jms.id.au>
Date:   Mon, 31 Jul 2023 04:21:18 +0000
Message-ID: <CACPK8Xf6YssamEmHB5XDf8JYk+_=hnG8Yzqn4kCikseqg6rqOA@mail.gmail.com>
Subject: Re: [PATCH] i2c: aspeed: Avoid accessing freed buffers during i2c transfers.
To:     Lixue Liang <lianglixuehao@126.com>,
        Eddie James <eajames@linux.ibm.com>
Cc:     brendan.higgins@linux.dev, benh@kernel.crashing.org,
        p.zabel@pengutronix.de, linux-i2c@vger.kernel.org,
        openbmc@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org,
        linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        Lixue Liang <lianglixue@greatwall.com.cn>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Fri, 28 Jul 2023 at 12:40, Lixue Liang <lianglixuehao@126.com> wrote:
>
> From: Lixue Liang <lianglixue@greatwall.com.cn>
>
> After waiting for the transmission timeout, the I2C controller will
> continue to transmit data when the bus is idle. Clearing bus->msg will
> avoid kernel panic when accessing the freed msg->buf in
> aspeed_i2c_master_irq.
>
> Signed-off-by: Lixue Liang <lianglixue@greatwall.com.cn>
> ---
>  drivers/i2c/busses/i2c-aspeed.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
> index 2e5acfeb76c8..c83057497e26 100644
> --- a/drivers/i2c/busses/i2c-aspeed.c
> +++ b/drivers/i2c/busses/i2c-aspeed.c
> @@ -713,6 +713,8 @@ static int aspeed_i2c_master_xfer(struct i2c_adapter *adap,
>                 spin_lock_irqsave(&bus->lock, flags);
>                 if (bus->master_state == ASPEED_I2C_MASTER_PENDING)
>                         bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
> +
> +               bus->msgs = NULL;

Eddie, is this the same issue you were debugging?

>                 spin_unlock_irqrestore(&bus->lock, flags);
>
>                 return -ETIMEDOUT;
> --
> 2.27.0
>