panic: deadlres_td_sleep_q: possible deadlock detected on RPI3

[bob prohaska]

On Thu, Jan 23, 2020 at 08:44:19AM -0800, bob prohaska wrote:
> My Pi3 running -current r356835 reported:
> 
> panic: deadlres_td_sleep_q: possible deadlock detected for 0xfffffd0000eff000, blocked for 1800305 ticks
> 
[backtrace omitted]

Attempts to reboot are also rebuffed with 
cpu_reset failed
leaving a power cycle as the only option, which is new to me.

Does this give any hints as to what's going on? 

Thanks for reading,

bob prohaska