Re: kern/59185: panic over KASSERTMSG(dev->ud_ifaces == NULL) on Dell Latitude 7490

[Michael van Elst <mlelstv%serpens.de@localhost>]

On Tue, Mar 18, 2025 at 10:01:48PM +0100, Emile `iMil' Heitor wrote:

> $ doas usbctl -f /dev/usb1 -a 5
> DEVICE addr 5
> DEVICE descriptor:
> bLength=18 bDescriptorType=device(1) bcdUSB=1.10 bDeviceClass=0 bDeviceSubClass=0
> bDeviceProtocol=0 bMaxPacketSize=64 idVendor=0x0a5c idProduct=0x5834 bcdDevice=101
> iManufacturer=1(Broadcom Corp) iProduct=2(5880) iSerialNumber=3(0123456789ABCD) bNumConfigurations=1
> 
> CONFIGURATION descriptor 0:
> bLength=9 bDescriptorType=config(2) wTotalLength=269 bNumInterface=4
> bConfigurationValue=0 iConfiguration=0() bmAttributes=e0 bMaxPower=100 mA
  ^^^^^^^^^^^^^^^^^^^^^

That's what our code doesn't handle correctly, as we abuse a value of 0 as 'unconfigured'.

usb_subr.c:906

bad:
        /* XXX Use usbd_set_config() to reset the config? */
		/* XXX Should we forbid USB_UNCONFIG_NO from bConfigurationValue? */



Greetings,
-- 
                                Michael van Elst
Internet: mlelstv%serpens.de@localhost
                                "A potential Snark may lurk in every tree."