Comment # 23 on bug 1017783 from Joey Lee

(In reply to Dominique Leuenberger from comment #21)
> possible related upstream bug:
> https://bugzilla.kernel.org/show_bug.cgi?id=192111

In bko#192111, Ivan bisected out that the bad patch is 8b355e3bc.

The result is possible because acpi/osl.c uses synchronize_rcu_expedited to
speed up grace period in acpi_os_map_cleanup() since v3.19:

74b51ee152b    ACPI / osl: speedup grace period in acpi_os_map_cleanup


The detail of 8b355e3bc needs RCU expert's comment.