[4.5.0.19] [XA2 Ultra] Race Condition in Lock-Screen

REPRODUCIBILITY: random (happend twice so far)
OS VERSION: 4.5.0.19
HARDWARE: XA2 Ultra
UI LANGUAGE: German
REGRESSION: don’t know

DESCRIPTION:

I have managed to to unlock my phone twice already without entering any code by swiping up on the lock screen.
My phone is set to instantly lock when turning the screen off / using the lock button.

My best guess is that there is a race condition which causes the phone to think that it is unlocked and thereby processing the “swipe up” as “show the application menu” instead of “show the camera from the lock screen”.

I don’t remember how much time passed between locking and unlocking the phone the first time. The second time i locked and unlocked as fast as i could.

PRECONDITIONS:

STEPS TO REPRODUCE:

  1. Press the “lock” button to lock the phone
  2. Press the “lock” button again to see the lock screen
  3. swipe up to open camera
  4. if you are lucky you will see your applications instead of the camera and your phone is unlocked

EXPECTED RESULT:

Not being able to unlock my phone without my code

ACTUAL RESULT:

Phone unlocked

MODIFICATIONS:

ADDITIONAL INFORMATION:

  • Android App Support is running
  • LUKS 1 is enabled
  • Numeric Lock Code
  • Phone is set to “instantly lock” when turning the screen off

I confirm. This bug appears sometimes on my X10-3. On my side the phone get locked after 5 minutes.
And the quick access to the camera is disabled.

I wonder if this is related: sometimes after unlocking a not-yet-timeout-PIN-locked phone, it enters PIN unlock screen after less than a second, momentarily showing the application/app drawer/app switcher. Then I must enter PIN again to continue.

So yeah, both of these sound like a race co dition…