@
tsys  compiles fine and working (well?) so far. FYI i have numerous debug messages similar to: (using PREEMPT and DEBUG_PREEMPT)
[   87.534574] BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u12:1/89
[   87.534588] caller is debug_smp_processor_id+0x20/0x30
[   87.534595] CPU: 3 PID: 89 Comm: kworker/u12:1 Not tainted 5.8.0-rc1-0.39-1-pinebookpro-hwaccel+ #1
[   87.534597] Hardware name: Pine64 Pinebook Pro (DT)
[   87.534605] Workqueue: writeback wb_workfn (flush-259:0)
[   87.534612] Call trace:
[   87.534618]  dump_backtrace+0x0/0x1e0
[   87.534622]  show_stack+0x18/0x30
[   87.534631]  dump_stack+0xbc/0x114
[   87.534635]  check_preemption_disabled+0xf8/0x110
[   87.534638]  debug_smp_processor_id+0x20/0x30
[   87.534644]  ext4_mb_new_blocks+0x1b0/0x4a0
[   87.534651]  ext4_ext_map_blocks+0x618/0xce0
[   87.534654]  ext4_map_blocks+0xec/0x580
[   87.534659]  ext4_writepages+0x598/0xa80
[   87.534666]  do_writepages+0x54/0x110
[   87.534673]  __writeback_single_inode+0x3c/0x1d0
[   87.534678]  writeback_sb_inodes+0x1f8/0x3e0
[   87.534682]  __writeback_inodes_wb+0x4c/0xf0
[   87.534686]  wb_writeback+0x1dc/0x1f0
[   87.534690]  wb_workfn+0x30c/0x350
[   87.534694]  process_one_work+0x190/0x320
[   87.534698]  worker_thread+0x4c/0x400
[   87.534704]  kthread+0x104/0x140
[   87.534709]  ret_from_fork+0x10/0x24