On Mon, 15 Aug 2016, Greg KH wrote: > On Mon, Aug 15, 2016 at 11:31:10AM -0700, Vaibhav Hiremath wrote: > > In case of HUB devices connected to USB ports, we may not have DT > > node representing it inside USB, and when devices connected to hub > > gets enumerated, call to usb_of_get_child_node() leads to NULL pointer > > dereference. > > Really? That seems messed up. > > > In the usecase we have, where EHCI port is connected to USB HUB > > device, and downward ports of HUB are connected to further USB > > devices. When those devices gets enumerated, in order, > > 1. USB HUB -> > > -> Call to usb_of_get_child_node() is OK, as > > parent->dev.of_node is pointing to host node. > > 2. Devices connected to downward port of USB HUB > > -> Call to usb_of_get_child_node() leads to NULL > > pointer dereference as parent->dev.of_node = NULL, > > as USB HUB DTS node may be empty. > > Why is the hub DTS empty? Shouldn't that be the fix here?
It's empty because there's no DT entry for the hub. That's normal; most USB devices aren't represented in DT because they aren't part of the original system -- they are added plugged in later. Or, it's possible that the hub _is_ part of the original system and it was left out of the DT database. Alan Stern
