RFR (S): 8024974 - Incorrect use of GC_locker::is_active()
Per Liden
per.liden at oracle.com
Wed Sep 18 23:03:29 PDT 2013
Webrev: http://cr.openjdk.java.net/~pliden/8024974/webrev.01/
Bug: https://bugs.openjdk.java.net/browse/JDK-8024974
SymbolTable and StringTable can make calls to GC_locker::is_active()
outside a safepoint. This isn't safe because the GC_locker active state
(lock count) is only updated at a safepoint and only remains valid as
long as _needs_gc is true. However, outside a safepoint _needs_gc can
change to false at any time, which makes it impossible to do a correct
call to is_active() in that context. In this case these calls can just
be removed since the input argument to basic_add() should never be on
the heap and so there's no need to check the GC_locker state. This
change also adjusts the assert() in is_active() to makes sure all calls
to this function are always done under a safepoint.
cheers,
/Per
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