Hello,

syzbot tried to test the proposed patch but build/boot failed:

patch is already applied


Tested on https://github.com/joelagnel/linux.git/test-ashmem commit
32f813bb0d06c1e189ac336f8c3c7377f85c71f0 (Wed Jan 24 01:45:04 2018 +0000)
ashmem: Fix lockdep issue during llseek

compiler: gcc (GCC) 7.1.1 20170620
Patch is attached.