SWT / anr problem - deadlock

1. Confirm the problem time point ：

02-25 04:05:23.019869  1126  3219 I watchdog: Blocked in monitor com.android.server.Watchdog$BinderThreadMonitor on foreground thread (android.fg), Blocked in handler on main thread (main), Blocked in handler on display thread (android.display), Blocked in handler on ActivityManager (ActivityManager)

2. Find twice in the corresponding time period trace It's consistent , All are as follows （ The following figure intercepts only one time point backtrace）：

First from system_server blocked Any of thread Start to analyze , Such as main thread：

----- pid 1126 at 2019-02-25 04:05:23 -----
Cmd line: system_server

"main" prio=5 tid=1 Blocked
| group="main" sCount=1 dsCount=0 flags=1 obj=0x73039dd0 self=0x75778c4a00
| sysTid=1126 nice=-2 cgrp=default sched=0/0 handle=0x75fcfc89a8
| state=S schedstat=