RE: [PATCH 03/16] IA64: use ACCESS_ONCE for rlimits

["Luck, Tony" <tony.luck@xxxxxxxxx>]

> Make sure compiler won't do weird things with limits. E.g. fetching
> them twice may return 2 different values after writable limits are
> implemented.

-	if (size > task->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
+	if (size > ACCESS_ONCE(task->signal->rlim[RLIMIT_MEMLOCK].rlim_cur))

I don't see how this helps.  If someone else is changing limits while
we are looking at them, then there is a race.  We either get the old
or the new value.  Using ACCESS_ONCE (which on ia64 forces a "volatile"
access, which will make the compiler generate "ld.acq" rather than a
plain "ld") won't make any difference to this race.

Please explain what issue you see with the current code.

-Tony

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