[tomp]

From my observations, there seem to have been considerable efforts to avoid it being just random. Compiler & library "optimisations" have broken Linux before ("randomly") [0] [3]. Linus has ranted about this [1], multiple times [2] [3].

[0] https://lwn.net/SubscriberLink/793253/6ff74ecfb804c410/

[1] https://lkml.org/lkml/2018/6/5/769

[2] https://bugzilla.redhat.com/show_bug.cgi?id=638477#c129

[3] http://lkml.iu.edu//hypermail/linux/kernel/1407.3/00650.html