On 20 June 2018 at 13:04, Benjamin Herrenschmidt
<benh@xxxxxxxxxxxxxxxxxxx> wrote:
> On Wed, 2018-06-13 at 14:36 -0500, Eddie James wrote:
>> }
>>
>> +static int fsi_i2c_remove(struct device *dev)
>> +{
>> + struct fsi_i2c_master *i2c = dev_get_drvdata(dev);
>> + struct fsi_i2c_port *port;
>> +
>> + list_for_each_entry(port, &i2c->ports, list) {
>> + i2c_del_adapter(&port->adapter);
>> + kfree(port);
>> + }
>> +
>> + return 0;
>> +}
>> +
>
> This is a use-after-free, the list linkage of the freed port is used to
> get to the next one. With memory poisoning, kbooom !
>
> You can fold that in:
>
> From f9d9092160897e7308f6990067a03e937339537f Mon Sep 17 00:00:00 2001
> From: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> Date: Wed, 20 Jun 2018 13:27:32 +1000
> Subject: [PATCH] i2c: fsi: Fix use after free
This fixes the issue I was seeing. For the series:
Tested-by: Joel Stanley <joel@xxxxxxxxx>
Thanks,
Joel
>
> Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-fsi.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c
> index 713959b44403..ff69ab6aa79a 100644
> --- a/drivers/i2c/busses/i2c-fsi.c
> +++ b/drivers/i2c/busses/i2c-fsi.c
> @@ -696,9 +696,10 @@ static int fsi_i2c_probe(struct device *dev)
> static int fsi_i2c_remove(struct device *dev)
> {
> struct fsi_i2c_master *i2c = dev_get_drvdata(dev);
> - struct fsi_i2c_port *port;
> + struct fsi_i2c_port *port, *tmp;
>
> - list_for_each_entry(port, &i2c->ports, list) {
> + list_for_each_entry_safe(port,tmp, &i2c->ports, list) {
> + list_del(&port->list);
> i2c_del_adapter(&port->adapter);
> kfree(port);
> }
>
