On 01/09/2017 08:41 AM, Daniel Vetter wrote: > On Mon, Jan 9, 2017 at 2:40 PM, Dave Hansen <dave.hansen@xxxxxxxxx> wrote: >> Well, now I found where the -2 comes from. >> intel_dp_register_mst_connector() calls drm_connector_register(), which >> fails to add the kobject (warning below). But, it does zero error >> checking on the drm_connector_register() call and leaves the >> partially-constructed connector in place. >> >> The next time some poor, hapless code goes and tries to do anything with >> that kdev, they oops. I'm perplexed by this, though. The >> drm_dp_mst_topology_cbs->register_connector just returns void. It seems >> a bit goofy that it can't even _return_ failure. >> >> Is there some stable code to go back to here? Or, is there something >> about my configuration that's unique? I really wonder why nobody else >> is running into this. >> >> There's probably some other race going on here. This warning doesn't >> happen on every boot. > This smells more like the root-cause: Something goes wrong on boot > that prevents connectors from properly registering, then we fall over > later on. And the register callback is intentionally void, assuming > that any prep work has been done earlier and that therefore the > register step can't fail. Can you pls check whether the oops later on > only happens together with this warning at boot, or whether they're > not correlated? Looking through my logs, I can't find any instance of the oops without the warning at boot. So I do think the later oops is entirely caused by the issue warned about in early boot. My distro kernel (4.4.0-57-generic) is also unstable, but I haven't managed to capture a good oops there. It's hitting this, which I assume is unrelated: WARNING: CPU: 0 PID: 41 at /build/linux-lts-xenial-FdAdUy/linux- lts-xenial-4.4.0/ubuntu/i915/intel_pm.c:3675 skl_update_other_pipe_wm+0x191/0x1a0 [i915_bpo]() _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
