From 80accdc4e0e1acd5d5e94f54f7176fa05d81b239 Mon Sep 17 00:00:00 2001
From: xlu <unknown>
Date: Tue, 13 Jan 2009 12:08:43 -0800
Subject: [PATCH] 6791815: Fix for 6471657 can cause deadlock on non-Solaris
 platforms when initializing direct buffer support Summary: Place the state
 transition inside the loop so that the VMThread could proceed for safepoint
 Reviewed-by: dholmes, never, acorn

---
 src/share/vm/prims/jni.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/share/vm/prims/jni.cpp b/src/share/vm/prims/jni.cpp
index b4a82b9e5..e3f715dd2 100644
--- a/src/share/vm/prims/jni.cpp
+++ b/src/share/vm/prims/jni.cpp
@@ -2691,8 +2691,13 @@ static bool initializeDirectBufferSupport(JNIEnv* env, JavaThread* thread) {
 
     directBufferSupportInitializeEnded = 1;
   } else {
-    ThreadInVMfromNative tivn(thread); // set state as yield_all can call os:sleep
     while (!directBufferSupportInitializeEnded && !directBufferSupportInitializeFailed) {
+      // Set state as yield_all can call os:sleep. On Solaris, yield_all calls
+      // os::sleep which requires the VM state transition. On other platforms, it
+      // is not necessary. The following call to change the VM state is purposely
+      // put inside the loop to avoid potential deadlock when multiple threads
+      // try to call this method. See 6791815 for more details.
+      ThreadInVMfromNative tivn(thread);
       os::yield_all();
     }
   }
-- 
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