Hi, Semyon.
The fix looks fine to me.
Thanks!
On 21.04.15 11:37, Semyon Sadetsky wrote:
Sergey,
done.
http://cr.openjdk.java.net/~ssadetsky/7155957/webrev.01/
--Semyon
On 4/16/2015 6:41 PM, Sergey Bylokhov wrote:
Hi, Semyon.
Please mark all related fields in WObjectPeer as volatile( pData/
destroyed/etc). Probably MenuComponent.font field also?
That could be a reason for similar random issues.
On 15.04.15 17:38, Semyon Sadetsky wrote:
Hello,
Please review fix for JDK9.
webrev: http://cr.openjdk.java.net/~ssadetsky/7155957/webrev.00/
bug: https://bugs.openjdk.java.net/browse/JDK-7155957
*THE ROOT CAUSE
A number of concurrency bugs in AWT Toolkit.
When menus are modified concurrently there is a big chance that the
internal Windows menu events are handled at the same time on the
AWT-Windows thread which is not synchronized. If the internal event
processing on AWT-Windows calls Java side methods the JVM can die
silently.
*SOLUTIONS
A number of fixes in various Java and C++ classes are introduced to
eliminate (with finite probability) concurrency problems :
1. java.awt.Menu.remove(int)
The peer.delItem(index) is called after mi.removeNotify(). That
means that dispose event will be sent earlier than the menu remove
WinAPI call. This causes Access Violation exception because Windows
events may come with deallocated references.
The solution is to call them in the right order.
2. java.awt.MenuBar.remove(int)
Same error as in 1 for menu bar.
3. java.awt.MenuComponent.serFont(Font)
This method should hold tree lock while running otherwise its
concurrent execution causes Access Violation in number of places and
JVM is crashed.
4. awt_Menu.cpp
AwtMenu::GetItem(jobject target, jint index), AwtMenu::DrawItems(),
AwtMenu::MeasureItems(
Calling java.awt.Menu.getItem() during internal windows event
processing can throw ArrayIndexOutOfBoundException because number of
menu items could be changed concurrently and the index is not in
range. This causes a hidden exception which is only seen in debug
mode as an Assertion error.
Another issue here is request to GetPeerForTarget() for the menu
item peer which can be concurrently deleted on the Java side as
result of Menu.delNotify() execution. It causes NPE peer which is
also hidden and only reveals itself as an Assertion error in debug
mode.
The solution for all is to abort and return windows event callback
if the menu structure was changed concurrently.
5. awt_MenuBar.cpp AwtMenuBar::GetItem()
Same solution as 4 for menu bar in similar situations.
6. awt_MenuItem.cpp AwtMenuItem::Dispose()
The "destroyed" filed should be set for the peer before pData is set
to NULL otherwise "NPE null pData" can be thrown in various
concurrent situations.
7. awt_new.cpp safe_ExceptionOccurred()
This routine is called evrywere in the code to check exceptions. It
only stops execution and prints to console if OOE happened, but
other exceptions are re-thrown silently and execution continues
without any warnings. If the call is initiated by an internal
Windows event callback the exceptions are hidden in the release mode
and shown in the debug mode as the Assertion Error message box, but
in the last case without any useful information because
GetLastError() is always 0 in such situations.
I have added env->ExceptionDescribe() to print exception stack trace
on the console for all debug and release modes. This should help to
detect internal toolkit issues during testing by JCK and jtreg.
Later before the JDK9 release we can leave it for debug mode only.
*A KNOWN PROBLEM DID NOT FIXED
When font is assigned to a menu item concurrently there is a big
chance that menu item size will be calculated with one font while
drawing of the item will be performed with another font. In such
situation label of the menu item does not fit its size or vice versa.
This is due to nature how the Windows OS handles owner-drawn menus.
--Semyon
--
Best regards, Sergey.
--
Best regards, Sergey.
