Request for reviews (S): 7196242: vm/mlvm/indy/stress/java/loopsAndThreads crashed

[Vladimir Kozlov]

Looks good.

Vladimir

Christian Thalinger wrote:
> http://cr.openjdk.java.net/~twisti/7196242
> 29 lines changed: 13 ins; 10 del; 6 mod; 2239 unchg
> 
> 7196242: vm/mlvm/indy/stress/java/loopsAndThreads crashed
> Reviewed-by:
> 
> The current code in ConstantPoolCacheEntry::set_method_handle_common uses 
> a CAS to find out who's the winning thread in the race about linking an 
> invokehandle/invokedynamic call site.  The winning thread does the linking 
> while the other threads are waiting in a loop until the winning thread 
> finishes.  The waiting threads enter the Patching_lock and call os::yield 
> to give the winning thread more CPU time.
> 
> Unfortunately the implementation of os::yield on Solaris uses the 
> Threads_lock and we hit this assert:
> 
> #  fatal error: acquiring lock Threads_lock/15 out of order with lock Patching_lock/1 -- possible deadlock
> 
> Even worse, the CAS might fail spuriously and we don't have a winning 
> thread because we don't loop around the CAS.  This may lead to hangs.
> 
> src/share/vm/interpreter/interpreterRuntime.cpp
> src/share/vm/oops/cpCache.cpp
> src/share/vm/oops/cpCache.hpp
>