bug#11956: misc/tty-eof: sometimes failure under heavy load

[Bernhard Voelker]

FAIL: misc/tty-eof (exit: 1)
============================

F: 1: YSBiCg==
F: 1: a b
F: 1: 780509149 4
F: 1: a b
F: 1: a b
F: 1: a b
F: 1: a b
F: 1: a b
F: 1: 7557d2f3a6ad1a3a8ebd23a94ab0c642  -
F: 1:      1    a b
F: 1: 0000000 020141 005142
F: 1: a b
F: 1:
F: 1:                                        a b
F: 1: 90ce62edf2fe4940e041a68b13e7b5f9d02bbf51  -
F: 1: afa36e61f94d23fa2869cc1ca3c7a0855ecb7f3d3305e446e7566d1f  -
F: 1: 01186fcf04b4b447f393e552964c08c7b419c1ad7a25c342a0b631b1967d3a27  -
F: 1: 
adf433b1ea7db8dec7ca64f88f4c8bc5403a1ac1d3540ae0229c79fc8d84e3db4dd9616605c61215ee7c50da0a97d0e2
  -
F: 1:
ae206702ea661de518d6451ee5b76fe0120429239b73838301991a294bc2628c0b9bbe79d06b1ab0610a66e9ce7d7e16cdcbdc244058befefc03c5d9cce54357
 -
F: 1: a b
tty-eof: sort didn't produce expected output
F: 1: 08271     1
tty-eof: tac didn't produce expected output
F: 1: a b
F: 1: a b
F: 1: a
F: 1: a b
F: 1: a b
F: 1:       1       2       4

I was running "make check-very-expensive -j 10 -l 4", and as misc/tty-eof
is quite at the top, "make" maybe didn't have a chance to balance to load
4 yet. It happens only under heavy load (CPU and disk), but I can not
reproduce it under "normal" conditions. However, with "-j 10 -l 4",
I hit it quite regularly (1 out of 4 times).

And sometimes, the "tac" error message is not there, only the "sort" error
is there.

Any idea what is going on?

Have a nice day,
Berny