- Fix flaw in win32k hardware message queue which used KMUTEX instead of KMUTANT, thus double-disabling Kernel APCs during the parsing of the queue, which would result in actually deliving hardware message callbacks with Kernel APCs disabled when going to user-mode. This was detected when my new user-mode callback rewrite added checks for this situation, and it originally caused a bugcheck. Since the message queue code is now fixed, the bugcheck has been re-enabled, hopefully no other such violations will be detected (I was able to run/install firefox for a couple of minutes and there was no APC_INDEX_MISMATCH crash). Fixes bug 1272, and thanks to Filip for doing some late-night IRC analysis with me.

Modified: trunk/reactos/ntoskrnl/ke/i386/usercall_asm.S
Modified: trunk/reactos/subsys/win32k/ntuser/msgqueue.c

--- trunk/reactos/ntoskrnl/ke/i386/usercall_asm.S	2006-01-14 04:32:37 UTC (rev 20845)
+++ trunk/reactos/ntoskrnl/ke/i386/usercall_asm.S	2006-01-14 08:49:10 UTC (rev 20846)
@@ -87,7 +87,6 @@

 
 AtPassive:
 

-#if 0

     /* Make sure that we are not attached and that APCs are not disabled */
     movzx eax, byte ptr [ebx+KTHREAD_APC_STATE_INDEX]
     mov edx, [ebx+KTHREAD_COMBINED_APC_DISABLE]
@@ -104,7 +103,6 @@

     push 0
     push APC_INDEX_MISMATCH
     call _KeBugCheckEx@20

-#endif

 ApcsEnabled:
 #endif
 

--- trunk/reactos/subsys/win32k/ntuser/msgqueue.c	2006-01-14 04:32:37 UTC (rev 20845)
+++ trunk/reactos/subsys/win32k/ntuser/msgqueue.c	2006-01-14 08:49:10 UTC (rev 20846)
@@ -46,7 +46,7 @@

 
 static ULONG volatile HardwareMessageQueueStamp = 0;
 static LIST_ENTRY HardwareMessageQueueHead;

-static KMUTEX HardwareMessageQueueLock;

+static KMUTANT HardwareMessageQueueLock;

 
 static KEVENT HardwareMessageEvent;
 
@@ -60,7 +60,7 @@

   KeReleaseSpinLock(&SystemMessageQueueLock, OldIrql)
 
 #define IntUnLockSystemHardwareMessageQueueLock(Wait) \

-  KeReleaseMutex(&HardwareMessageQueueLock, Wait)

+  KeReleaseMutant(&HardwareMessageQueueLock, IO_NO_INCREMENT, FALSE, Wait)

 
 /* FUNCTIONS *****************************************************************/
 
@@ -122,7 +122,7 @@

    InitializeListHead(&HardwareMessageQueueHead);
    KeInitializeEvent(&HardwareMessageEvent, NotificationEvent, 0);
    KeInitializeSpinLock(&SystemMessageQueueLock);

-   KeInitializeMutex(&HardwareMessageQueueLock, 0);

+   KeInitializeMutant(&HardwareMessageQueueLock, 0);

 
    ExInitializePagedLookasideList(&MessageLookasideList,
                                   NULL,