Sorry I wanted to include a pastebin or link but was trying to follow maillist guidelines and not include links or exceed wrap guidelines. Full contents: https://paste.centos.org/view/3746bc40 Yes I understand the return dodges the config dereference. Original line usb.c:281 is the original error: 280| for (i = 0; i < config->desc.bNumInterfaces; i++) 281| if (config->interface[i]->altsetting[0] 282| .desc.bInterfaceNumber == ifnum) 283| return config->interface[i]; Thanks John On Fri, Nov 13, 2020 at 4:34 PM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > On Fri, Nov 13, 2020 at 01:18:05PM +0000, John Boero wrote: > > Thanks for the tips. > > > > I've spent some more time on this this morning. > > It looks like it's not the dev after all. > > What isn't the dev? > > > Every interface in the dev is set NULL after init. > > I can't tell what this means. Please be more explicit. > > > Just like in the original Ubuntu bug 1827452 filed by someone else > > the device seems to disconnect itself after uvcvideo initialization. > > Then there is a 5 second pause before usb_ifnum_to_if tries > > to iterate through its 8 interfaces - all of which are null. > > It looks like uvc properly locks the dev, so maybe this could > > be caused by any device being unplugged after init? > > More likely there is a bug in the uvcvideo driver. > > > The WARNING handle preserves USB function though, > > and subsequent lsusb behaves fine: > > No, the WARN only writes a message to the system log. The "return" > statement is what prevented the system from crashing. > > > $ lsusb | fold -w 80 > > Bus 002 Device 002: ID 8087:8002 Intel Corp. 8 channel internal hub > > Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > > Bus 001 Device 002: ID 8087:800a Intel Corp. Hub > > Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > > Bus 004 Device 002: ID 0451:8140 Texas Instruments, Inc. TUSB8041 4-Port Hub > > Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub > > Bus 003 Device 005: ID 1ea7:0064 SHARKOON Technologies GmbH 2.4GHz Wireless rech > > argeable vertical mouse [More&Better] > > Bus 003 Device 004: ID 145f:025c Trust Trust USB Microphone > > Bus 003 Device 002: ID 1050:0407 Yubico.com Yubikey 4/5 OTP+U2F+CCID > > Bus 003 Device 009: ID 0a5c:21e8 Broadcom Corp. BCM20702A0 Bluetooth 4.0 > > Bus 003 Device 008: ID 0451:8142 Texas Instruments, Inc. TUSB8041 4-Port Hub > > Bus 003 Device 006: ID 062a:4101 MosArt Semiconductor Corp. Wireless Keyboard/Mo > > use > > Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > > Bus 006 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub > > Bus 005 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > > > > 8x (0-7) occurences of the following WARNING: > > > > [ 140.678756] usb 3-4: USB disconnect, device number 3 > > [ 145.995855] ------------[ cut here ]------------ > > [ 145.995863] dev interface is NULL in usb_ifnum_to_if > > [ 145.995907] WARNING: CPU: 31 PID: 5617 at drivers/usb/core/usb.c:289 > > usb_ifnum_to_if+0x58/0x80 > > You removed the most important part of the log message! What appears > below this point? > > In fact, you should just post the entire log (or put it on a server > somewhere and post a URL). > > Alan Stern
