Re: [PATCH] i2c: aspeed: Avoid accessing freed buffers during i2c transfers.

Re: [PATCH] i2c: aspeed: Avoid accessing freed buffers during i2c transfers.

[Joel Stanley]

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
>

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Re: [PATCH] i2c: aspeed: Avoid accessing freed buffers during i2c transfers.

[Eddie James]

On 7/31/23 01:10, Lei YU wrote:
> There is a same fix in 
> https: //lore. kernel. org/openbmc/374237cb-1cda-df12-eb9f-7422cab51fc4@ linux. alibaba. com/ 
> On Mon, Jul 31, 2023 at 12: 21 PM Joel Stanley <joel@ jms. id. au> 
> wrote: On Fri, 28 Jul 2023 at 12: 40, Lixue Liang 
> <lianglixuehao@ 126. com>
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> There is a same fix in 
> https://lore.kernel.org/openbmc/374237cb-1cda-df12-eb9f-7422cab51fc4@linux.alibaba.com/
>
> On Mon, Jul 31, 2023 at 12:21 PM Joel Stanley <joel@jms.id.au> wrote:
>
>     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?
>

Yes, it is, and the same fix I settled on.


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

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Re: [PATCH] i2c: aspeed: Avoid accessing freed buffers during i2c transfers.

[Andi Shyti]

Hi Lixue,

On Fri, Jul 28, 2023 at 12:24:16PM +0000, Lixue Liang 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.

actually in aspeed_i2c_master_irq() you are already checking for
!bus->msgs.

What kind of panic are you referring to?

Andi

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

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