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

[PATCH] 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.

Allocate some memory and put the currently separate error message in
it, and use it as the error message. If the allocation fails, use a
generic version of the error message. The allocation uses devres
helpers, and will be freed after the message is printed and the device
is cleaned up.

Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
---
 drivers/usb/core/hub.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index b09b43669658..fc4879d9c623 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1751,8 +1751,15 @@ static int hub_configure(struct usb_hub *hub,
 	for (i = 0; i < maxchild; i++) {
 		ret = usb_hub_create_port_device(hub, i + 1);
 		if (ret < 0) {
-			dev_err(hub->intfdev,
-				"couldn't create port%d device.\n", i + 1);
+			char *msg;
+
+			msg = devm_kasprintf(hub->intfdev, GFP_KERNEL,
+					     "couldn't create port%d device",
+					     i + 1);
+			if (msg)
+				message = msg;
+			else
+				message = "couldn't create port device";
 			break;
 		}
 	}
-- 
2.55.0.229.g6434b31f56-goog

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

[Andy Shevchenko]

On Tue, Jul 28, 2026 at 06:00:04PM +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.
> 
> Allocate some memory and put the currently separate error message in
> it, and use it as the error message. If the allocation fails, use a
> generic version of the error message. The allocation uses devres
> helpers, and will be freed after the message is printed and the device
> is cleaned up.

The 'message' is local to the function, why devm?
Shouldn't __free() be sufficient?

-- 
With Best Regards,
Andy Shevchenko

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

[Chen-Yu Tsai]

On Tue, Aug 11, 2026 at 12:31 AM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Tue, Jul 28, 2026 at 06:00:04PM +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.
> >
> > Allocate some memory and put the currently separate error message in
> > it, and use it as the error message. If the allocation fails, use a
> > generic version of the error message. The allocation uses devres
> > helpers, and will be freed after the message is printed and the device
> > is cleaned up.
>
> The 'message' is local to the function, why devm?
> Shouldn't __free() be sufficient?

I hadn't thought of that.

The scope shouldn't be a problem, since it's declared and used at the top
level. But we'd need a kfree_const() variant of __free(kfree). All the
other error messages are just plain C string constants.


ChenYu

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

[Andy Shevchenko]

On Tue, Aug 11, 2026 at 11:51:07AM +0800, Chen-Yu Tsai wrote:
> On Tue, Aug 11, 2026 at 12:31 AM Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> > On Tue, Jul 28, 2026 at 06:00:04PM +0800, Chen-Yu Tsai wrote:

...

> > The 'message' is local to the function, why devm?
> > Shouldn't __free() be sufficient?
> 
> I hadn't thought of that.
> 
> The scope shouldn't be a problem, since it's declared and used at the top
> level. But we'd need a kfree_const() variant of __free(kfree). All the
> other error messages are just plain C string constants.

Sure, I just sent a patch.

-- 
With Best Regards,
Andy Shevchenko