[patch] usb: gadget: f_midi: missing unlock on error path

[patch] usb: gadget: f_midi: missing unlock on error path

[Dan Carpenter]

We added a new error path to this function and we forgot to drop the
lock.

Fixes: e1e3d7ec5da3 ('usb: gadget: f_midi: pre-allocate IN requests')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index fb1fe96d..92b9ec8 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -1213,8 +1213,10 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
 	midi->in_last_port = 0;
 
 	status = kfifo_alloc(&midi->in_req_fifo, midi->qlen, GFP_KERNEL);
-	if (status)
+	if (status) {
+		mutex_unlock(&opts->lock);
 		goto setup_fail;
+	}
 
 	++opts->refcnt;
 	mutex_unlock(&opts->lock);

Re: [patch] usb: gadget: f_midi: missing unlock on error path

[Felipe Ferreri Tonello]

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Hi Dan,

On 21/12/15 13:20, Dan Carpenter wrote:
> We added a new error path to this function and we forgot to drop the
> lock.
> 
> Fixes: e1e3d7ec5da3 ('usb: gadget: f_midi: pre-allocate IN requests')
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
> index fb1fe96d..92b9ec8 100644
> --- a/drivers/usb/gadget/function/f_midi.c
> +++ b/drivers/usb/gadget/function/f_midi.c
> @@ -1213,8 +1213,10 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
>  	midi->in_last_port = 0;
>  
>  	status = kfifo_alloc(&midi->in_req_fifo, midi->qlen, GFP_KERNEL);
> -	if (status)
> +	if (status) {
> +		mutex_unlock(&opts->lock);

This is fine. But looking into this further, I believe this mutex_unlock
should be under the setup_fail label, because even if the alloc() fails,
it will be need to unlock the mutex in any circumstance anyway.

>  		goto setup_fail;
> +	}
>  
>  	++opts->refcnt;
>  	mutex_unlock(&opts->lock);
> 

Felipe

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Re: [patch] usb: gadget: f_midi: missing unlock on error path

[SF Markus Elfring]

> We added a new error path to this function and we forgot to drop the lock.
> 
> Fixes: e1e3d7ec5da3 ('usb: gadget: f_midi: pre-allocate IN requests')
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
> index fb1fe96d..92b9ec8 100644
> --- a/drivers/usb/gadget/function/f_midi.c
> +++ b/drivers/usb/gadget/function/f_midi.c
> @@ -1213,8 +1213,10 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi)
>  	midi->in_last_port = 0;
>  
>  	status = kfifo_alloc(&midi->in_req_fifo, midi->qlen, GFP_KERNEL);
> -	if (status)
> +	if (status) {
> +		mutex_unlock(&opts->lock);
>  		goto setup_fail;
> +	}
>  
>  	++opts->refcnt;
>  	mutex_unlock(&opts->lock);

How do you think about to move this unlock call and the one that belongs to
the handling of a kstrdup() failure below the shown jump target?

Regards,
Markus