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Message-ID: <ad5e5438-4a3f-2447-4af3-7caa91e7252a@linux.alibaba.com>
Date: Tue, 11 Jan 2022 15:52:25 +0800
From: Heyi Guo <guoheyi@...ux.alibaba.com>
To: linux-kernel@...r.kernel.org
Cc: Brendan Higgins <brendanhiggins@...gle.com>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Joel Stanley <joel@....id.au>,
Andrew Jeffery <andrew@...id.au>,
Philipp Zabel <p.zabel@...gutronix.de>,
linux-i2c@...r.kernel.org, openbmc@...ts.ozlabs.org,
linux-arm-kernel@...ts.infradead.org, linux-aspeed@...ts.ozlabs.org
Subject: Re: [PATCH] drivers/i2c-aspeed: avoid invalid memory reference after
timeout
Hi all,
Any comments?
Thanks,
Heyi
在 2022/1/9 下午9:26, Heyi Guo 写道:
> The memory will be freed by the caller if transfer timeout occurs,
> then it would trigger kernel panic if the peer device responds with
> something after timeout and triggers the interrupt handler of aspeed
> i2c driver.
>
> Set the msgs pointer to NULL to avoid invalid memory reference after
> timeout to fix this potential kernel panic.
>
> Signed-off-by: Heyi Guo <guoheyi@...ux.alibaba.com>
>
> -------
>
> Cc: Brendan Higgins <brendanhiggins@...gle.com>
> Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
> Cc: Joel Stanley <joel@....id.au>
> Cc: Andrew Jeffery <andrew@...id.au>
> Cc: Philipp Zabel <p.zabel@...gutronix.de>
> Cc: linux-i2c@...r.kernel.org
> Cc: openbmc@...ts.ozlabs.org
> Cc: linux-arm-kernel@...ts.infradead.org
> Cc: linux-aspeed@...ts.ozlabs.org
> ---
> drivers/i2c/busses/i2c-aspeed.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
> index 67e8b97c0c950..3ab0396168680 100644
> --- a/drivers/i2c/busses/i2c-aspeed.c
> +++ b/drivers/i2c/busses/i2c-aspeed.c
> @@ -708,6 +708,11 @@ 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;
> + /*
> + * All the buffers may be freed after returning to caller, so
> + * set msgs to NULL to avoid memory reference after freeing.
> + */
> + bus->msgs = NULL;
> spin_unlock_irqrestore(&bus->lock, flags);
>
> return -ETIMEDOUT;
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