This patch modifies the usb_device_info() function to enumerate active USB hubs by iterating UCLASS_USB_HUB directly.
The previous code used UCLASS_USB nodes instead and retrieved their first child node, expecting it to be a hub. However, it did not protect against retrieving (and dereferencing) a NULL pointer this way.
Depending on the available USB hardware, this might happen easily. For example the USB controller on sun7i-a20 has top-level OHCI nodes that won't have any children as long as no USB1-only peripheral is attached. ("usb tree" will only show EHCI nodes.)
The failure can also be demonstrated with U-Boot's sandbox architecture, by simply enabling the inactive "usb_2" node in test.dts. This creates a similar situation, where the existing usb_device_info() implementation would crash (segfault) when issuing a "usb info" command.
Signed-off-by: Bernhard Nortmann bernhard.nortmann@web.de
---
cmd/usb.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-)
diff --git a/cmd/usb.c b/cmd/usb.c index 58d9db2..3146f54 100644 --- a/cmd/usb.c +++ b/cmd/usb.c @@ -602,18 +602,13 @@ static void show_info(struct udevice *dev)
static int usb_device_info(void) { - struct udevice *bus; - - for (uclass_first_device(UCLASS_USB, &bus); - bus; - uclass_next_device(&bus)) { - struct udevice *hub; + struct udevice *hub;
- device_find_first_child(bus, &hub); - if (device_get_uclass_id(hub) == UCLASS_USB_HUB && - device_active(hub)) { + for (uclass_first_device(UCLASS_USB_HUB, &hub); + hub; + uclass_next_device(&hub)) { + if (device_active(hub)) show_info(hub); - } }
return 0;