On Wed, Aug 26, 2026 at 11:19:33AM +0200, Greg Kroah-Hartman wrote: > The ability to add and remove devices from a driver through the sysfs > "bind" and "unbind" files was created all those decades ago as a way > that kernel developers can iterate faster, and provide a debugging way > for users to attempt to add a new device to a driver without having to > rebuild their kernel. > > This api over the years has been abused and recently come under a major > fuzzing "attack" through tools like syzbot which decided that it would > attempt to just randomly bind any driver to any type of device, causing > loads of unneeded errors and pointless kernel patches to be generated by > unsuspecting new developers. > > Handle all of this by adding a new taint flag, TAINT_FORCED_BIND, which > will be set on the driver if the bind/unbind sysfs files are ever > successfully written to. This lets kernel developers "know" that a user > is attempting to do something that is not normal, and as such, if the > kernel breaks they get to keep the shiny pieces laying around on the > floor. > > Note, the taint flag gets set _BEFORE_ the bind/unbind callback happens, > as many times crashes/oops/warnings/failures happen within the callback, > and the taint flag needs to be there to show what was being attempted. > If it were to be set after the callback happens, the oops report would > not properly reflect what foolishness was being attempted. > > Signed-off-by: Greg Kroah-Hartman <[email protected]>
This makes it clear that this is a development tool, and it is a good compromise preferable to adding unnecessary complexity or suppressing the attributes completely just to prevent root from shooting themselves in the foot: Reviewed-by: Johan Hovold <[email protected]> Tested-by: Johan Hovold <[email protected]> Johan
