KDBUS Is Being Removed From Fedora, Could Be A While Before Being Mainlined

In somewhat of an embarrassing move and indicating that KDBUS likely won't be proposed for Linux 4.4, this in-kernel IPC mechanism is being temporarily stripped out of Fedora.

Fedora developers added KDBUS to their Rawhide kernel this summer at the request of the systemd developers involved in KDBUS development. With systemd 221, the upstream developers also encouraged Linux distributions to begin shipping KDBUS even though it wasn't part of the mainline kernel. This turned out to be a mistake.

The developers requested KDBUS be removed from Fedora as they want to "rethink some of the approach they are taking with kdbus." Fedora kernel maintainer Josh Boyer noted this on their mailing list.

With now coming to the point of re-thinking some design decisions, it's good that it didn't land as originally planned for Linux 4.1 and it hasn't ended up being proposed since then. The Linux 4.4 merge window is expected to open next week, but given this latest communication, it seems highly unlikely KDBUS will be proposed for this next kernel cycle if they're going back to the drawing board. On the user-space side, KDBUS support has already been shipping with systemd for several stable releases.