I have a samsung galaxy s8 AT&T phone. USB tethering is not working on it. I have the Android tools slackbuild installed, ADB works, but my download speeds remain unchanged. I am using DHCPD (or however it's spelled), because my PC uses an ethernet cable instead of wireless.

dmesg shows the USB device connecting, but no further messages.
what must I do to get USB tethering working?

in addition I need some advice when it comes to picking some VM software for USB passthrough. I wish to use it to install a VM of windows 7, so I can run odin and flash a custom rom to my phone. I do not trust wine to work smoothly with odin, so I am opting to use a VM.

I used to use Virtualbox, but I'm wondering if there's something else- like QEMU or some kind of addon that would be more straightforward to setup.

should I stick with virtualbox or pick something different?

Your question has more to do with linux networking than with slackware, and might be more suited for LQ's linux-networking forum. If there's an issue with slackware that prevents usb-tethering then you are at the right place, but for anyone to be of assistance, you would have to provide heaps more information, such as what version of slackware you are running for starters. Since you are already here, however, I would suggest that if you are more comfortable in a GUI configuration environment, go for virtualbox; if you are more comfortable in a CLI configuration environment, then fire up qemu. As far as your usb tethering, assuming that your phone is connected to your computer via usb, and that the phone has had tethering enabled on it, does the "usb0" interface show up in the results of the "ifconfig" command, when run on your computer? Sounds like it must if dmesg sees it. Have you tried merely "dhclient -v usb0"," or configuring /etc/rc.d/rc.inet1.conf and running /etc/rc.d/rc.inet1?

Instead of Odin on a VM with USB pass through have you considered Heimdall? I've used it for years to root Samsung Galaxy phones. Rooting a Google Pixel is next on my todo list so I hope Heimdall works on that too.

As far as I know, heimdall is just used for Samsung devices. You use fastboot to unlock the bootloader, which is part of the android-tools package found on SBo.

You boot into the bootloader mode (press and hold volume down while starting up the phone), then issue fastboot flashing unlock and then agree to your phone being wiped. However, prior to doing that, you need to boot up the phone, enabled developer mode (tapping on Build ID 7 times), then enable bootloader unlocking under the developer options.

running "dhclient -v usb0" gets it working, thank you! would I need to run this every time I start up slackware? if yes, how would I set this up to run on boot so I don't need to set anything else up further?

bassmadrigal is right, heimdall is samsung exclusive. I'm trying to install this rom here. I'm gonna go check and ask there if heimdall works with it, but I'm a little leery on using heimdall because there's this nagging doubt in my mind that says something might get screwed up and my phone'll get bricked if I use it.

It was just a suggestion to use Heimdall. Always use the tool(s) you're most comfortable with.

If it is always hooked up, you would just need to adjust your /etc/rc.d/rc.inet1.conf file to change one of the devices from ethX to usb0 and set DHCP to yes. This should connect to it automatically during bootup.