[PATCH v3] 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.

Use a small buffer on the stack to put the custom formatted error message
in and use it as the error message.

Assisted-by: LLM # local reviews
Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
---
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@xxxxxxxxxxxx/

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 | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 0e929a4c9fa1..d7f39e86b24c 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1480,6 +1480,7 @@ static int hub_configure(struct usb_hub *hub,
 	unsigned int pipe;
 	int maxp, ret, i;
 	char *message = "out of memory";
+	char msg_buf[32] = {};
 	unsigned unit_load;
 	unsigned full_load;
 	unsigned maxchild;
@@ -1756,8 +1757,8 @@ 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);
+			snprintf(msg_buf, sizeof(msg_buf), "couldn't create port%d device", i + 1);
+			message = msg_buf;
 			break;
 		}
 	}
-- 
2.56.0.rc1.315.gc6ed9934b7-goog