What does Watchdog !@Sync error indicate?

Question

Android logcat gives me an error of E/Watchdog( 747): !@Sync 12552. The 747 I would guess is the PID and 12552 seems to be a counter as it is incremented with each occurrence.

What does Watchdog !@Sync error indicate?

Answer 1

Considering this (pre-KitKat) and this (KitKat) website:

Android framework's watchdog is meant to deal with cases when any of the following locks is held for more than a minute or when ServerThread is busy.

• ActivityManagerService.this
• PowerManagerService.mLocks
• WindowManagerService.mWindowMap
• WindowManagerService.mKeyguardTokenWatcher
• WindowManagerService.mKeyWaiter

So, the error is related to that.

For KitKat it could also be a package manager not responding for 10 minutes or another custom implementation, see KitKat link above.