[PATCH v4] usb: hub: Set proper message when usb_hub_create_port_device() fails

[PATCH v4] usb: hub: Set proper message when usb_hub_create_port_device() fails

[Chen-Yu Tsai]

Right now when usb_hub_create_port_device() fails, it prints a separate
error message to say which port failed, but otherwise leaves |message|
set to the default "out of memory", which is somewhat misleading.

Set |message| to an error message that is more specific to this error
path instead of using the default "out of memory" message.

Assisted-by: LLM # local reviews
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
Changes since v3:
- Print custom error message directly and use generic error message for
  later, instead of using more stack space

Changes since v2:
- Simplify to just using a small buffer on the stack (Alan)

Changes since v1:
- Explicitly track and free the allocated custom error message instead
  of using devm_kasprintf()
- Link to v1:
  https://lore.kernel.org/all/20260728100005.413868-1-wenst@chromium.org/

Sorry Andy, I ended up not using your __free(kfree_const) patch. My LLM
was telling me that it won't work correctly if CONFIG_USB=m.
---
 drivers/usb/core/hub.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 0e929a4c9fa1..4c85fdf7a233 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1758,6 +1758,7 @@ static int hub_configure(struct usb_hub *hub,
 		if (ret < 0) {
 			dev_err(hub->intfdev,
 				"couldn't create port%d device.\n", i + 1);
+			message = "couldn't create port device";
 			break;
 		}
 	}
-- 
2.56.0.385.gd3acb90ef8-goog

Re: [PATCH v4] usb: hub: Set proper message when usb_hub_create_port_device() fails

[Andy Shevchenko]

On Mon, Oct 12, 2026 at 05:27:24PM +0800, Chen-Yu Tsai wrote:
> Right now when usb_hub_create_port_device() fails, it prints a separate
> error message to say which port failed, but otherwise leaves |message|
> set to the default "out of memory", which is somewhat misleading.
> 
> Set |message| to an error message that is more specific to this error
> path instead of using the default "out of memory" message.

...

>  		if (ret < 0) {
>  			dev_err(hub->intfdev,
>  				"couldn't create port%d device.\n", i + 1);
> +			message = "couldn't create port device";
>  			break;

We can now even use

			message = "couldn't create port device";
			dev_err(hub->intfdev, "%s %d.\n", message, + 1);

>  		}

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4] usb: hub: Set proper message when usb_hub_create_port_device() fails

[Andy Shevchenko]

On Mon, Oct 12, 2026 at 11:53:04PM +0300, Andy Shevchenko wrote:
> On Mon, Oct 12, 2026 at 05:27:24PM +0800, Chen-Yu Tsai wrote:

...

> >  		if (ret < 0) {
> >  			dev_err(hub->intfdev,
> >  				"couldn't create port%d device.\n", i + 1);
> > +			message = "couldn't create port device";
> >  			break;
> 
> We can now even use
> 
> 			message = "couldn't create port device";
> 			dev_err(hub->intfdev, "%s %d.\n", message, + 1);

Of course this has to be

			dev_err(hub->intfdev, "%s %d.\n", message, i + 1);

but in any case it's up to you depending on the template used for the rest of
the messages in this function.

> >  		}

-- 
With Best Regards,
Andy Shevchenko