Re: [PATCH v5 5/5] firmware: imx: adds miscdev

[Sascha Hauer]

Hi Frank,

On Fri, Jul 12, 2024 at 06:19:22PM -0400, Frank Li wrote:
> > +	rx_msg = kzalloc(cmd_snd_rcv_rsp_info.rx_buf_sz, GFP_KERNEL);
> > +	if (!rx_msg) {
> > +		err = -ENOMEM;
> > +		goto exit;
> > +	}
> > +
> > +	tx_msg = memdup_user(cmd_snd_rcv_rsp_info.tx_buf,
> > +			     cmd_snd_rcv_rsp_info.tx_buf_sz);
> > +	if (IS_ERR(tx_msg)) {
> > +		err = PTR_ERR(tx_msg);
> > +		goto exit;
> > +	}
> > +
> > +	if (tx_msg->header.tag != priv->cmd_tag) {
> > +		err = -EINVAL;
> > +		goto exit;
> > +	}
> > +
> > +	scoped_guard(mutex, &priv->se_if_cmd_lock);
> 
> You totally wrong use scoped_guard in whole patch.
> 
> fun()
> {
>      guard(); //which means lock here
>      ...
>      return; // unlock here
> }
> 
> scoped_guard()
> {     // lock here
>       ...
>       //unlock here
> }
> 
> your code scoped_guard(mutex, &priv->se_if_cmd_lock);
> is equal to
>  
>       mutex_lock();
>       mutex_unlock();
> 
> Nothing protected by mutex lock at all.

Thanks for bringing this on the table again. I already mourned about
this in v2 of this series, but didn't notice the issue wasn't fixed
then.

Sascha

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