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

["Michael van Elst via gnats" <gnats-admin%NetBSD.org@localhost>]

The following reply was made to PR kern/59185; it has been noted by GNATS.

From: Michael van Elst <mlelstv%serpens.de@localhost>
To: Emile `iMil' Heitor <imil%home.imil.net@localhost>
Cc: gnats-bugs%netbsd.org@localhost, kern-bug-people%netbsd.org@localhost,
	gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Subject: Re: kern/59185: panic over KASSERTMSG(dev->ud_ifaces == NULL) on
 Dell Latitude 7490
Date: Wed, 19 Mar 2025 00:09:54 +0100

 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."