Unclear how, but the locking routine for mutexes was using the *release*
barrier instead of acquire. This must have been either a copy-pasto or bad
completion.
Going through other uses of atomics shows no barriers in:
- upgrade routines (addressed in this patch)
- sections protected with turnstile locks - this should be fine as necessary
barriers are in the worst case provided by turnstile unlock
I would like to thank Mark Millard and andreast@ for reporting the problem and
testing previous patches before the issue got identified.
ps.
.-'---`-.
,' `.
| \
| \
\ _ \
,\ _ ,'-,/-)\
( * \ \,' ,' ,'-)
`._,) -',-')
\/ ''/
) / /
/ ,'-'
Hardware provided by: IBM LTC
a21018063b