Hi Stephen,
On Thu, Sep 17, 2015 at 07:00:10PM -0400, cpaul@xxxxxxxxxx wrote:
> Responses
> * Re: if (!userio) in userio_device_write(): it happens if we close the file
> descriptor while the input driver is trying to talk to the device, since we
> can't immediately bring down the driver. Removing the condition breaks the
> driver
...
> +/**
> + * userio_device_write - Write data from serio to a userio device in userspace
> + * @id: The serio port for the userio device
> + * @val: The data to write to the device
> + */
> +static int userio_device_write(struct serio *id, unsigned char val)
> +{
> + struct userio_device *userio = id->port_data;
> +
> + if (!userio)
> + return -1;
1. I do not see where we reset port data.
2. I do not see what prevents object to which you now have a pointer to
from disappearing at any moment past your check.
> +
> + mutex_lock(&userio->lock);
serio_write() must allow to be called from interrupt context, so you
can't use mutex here.
Thanks.
--
Dmitry
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