An update to my post on TAINT_FORCED_BIND, the Linux 7.4 taint meant to flag bug reports from AI fuzz bots binding random drivers to random devices.
What changed
It’s been reverted. Turns out VFIO users rely on sysfs bind/unbind to detach PCIe devices from host drivers and hand them to vfio-pci for VM passthrough, so normal workflows would have tainted the kernel. Greg Kroah-Hartman called VFIO “a crazy beast” and pulled the feature for now. The revert was merged Friday night.
The likely path forward is Uwe Kleine-König’s idea: taint only when driver_override is used, with it off by default. That will be revisited after 7.4. Greg says syzbot has stopped doing this, “but in this madness of LLMs these days, you can’t be sure.”
My take
Classic xkcd 1172: every change breaks someone’s workflow. If you do GPU passthrough on Linux, this one would have hit you. Good on the kernel folks for backing it out fast.
God Bless, and Use the Source!
