--- //depot/projects/smpng/sys/amd64/amd64/trap.c	2006/01/06 20:21:45
+++ //depot/user/jhb/lock/amd64/amd64/trap.c	2006/01/06 21:17:48
@@ -237,8 +237,16 @@
 		 * do the VM lookup, so just consider it a fatal trap so the
 		 * kernel can print out a useful trap message and even get
 		 * to the debugger.
+		 *
+		 * If we get a page fault while holding a non-sleepable
+		 * lock, then it is most likely a fatal kernel page fault.
+		 * If WITNESS is enabled, then it's going to whine about
+		 * bogus LORs with various VM locks, so just skip to the
+		 * fatal trap handling directly.
 		 */
-		if (td->td_critnest != 0)
+		if (td->td_critnest != 0 ||
+		    WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL,
+		    "Kernel page fault") != 0)
 			trap_fatal(&frame, frame.tf_addr);
 	}
 
--- //depot/projects/smpng/sys/i386/i386/trap.c	2006/01/06 20:21:45
+++ //depot/user/jhb/lock/i386/i386/trap.c	2006/01/06 21:17:48
@@ -265,12 +265,20 @@
 		 * do the VM lookup, so just consider it a fatal trap so the
 		 * kernel can print out a useful trap message and even get
 		 * to the debugger.
+		 *
+		 * If we get a page fault while holding a non-sleepable
+		 * lock, then it is most likely a fatal kernel page fault.
+		 * If WITNESS is enabled, then it's going to whine about
+		 * bogus LORs with various VM locks, so just skip to the
+		 * fatal trap handling directly.
 		 */
 		eva = rcr2();
-		if (td->td_critnest == 0)
+		if (td->td_critnest != 0 ||
+		    WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL,
+		    "Kernel page fault") != 0)
+			trap_fatal(&frame, eva);
+		else
 			enable_intr();
-		else
-			trap_fatal(&frame, eva);
 	}
 
         if ((ISPL(frame.tf_cs) == SEL_UPL) ||
--- //depot/projects/smpng/sys/sys/lock.h	2006/01/17 17:16:05
+++ //depot/user/jhb/lock/sys/lock.h	2006/01/24 22:27:09
@@ -268,6 +269,9 @@
 #define	WITNESS_UNLOCK(lock, flags, file, line)				\
 	witness_unlock((lock), (flags), (file), (line))
 
+#define	WITNESS_CHECK(flags, lock, fmt, ...)				\
+	witness_warn((flags), (lock), (fmt), ## __VA_ARGS__)
+
 #define	WITNESS_WARN(flags, lock, fmt, ...)				\
 	witness_warn((flags), (lock), (fmt), ## __VA_ARGS__)
 
@@ -296,6 +300,7 @@
 #define	WITNESS_UPGRADE(lock, flags, file, line)
 #define	WITNESS_DOWNGRADE(lock, flags, file, line)
 #define	WITNESS_UNLOCK(lock, flags, file, line)
+#define	WITNESS_CHECK(flags, lock, fmt, ...)	0
 #define	WITNESS_WARN(flags, lock, fmt, ...)
 #define	WITNESS_SAVE_DECL(n)
 #define	WITNESS_SAVE(lock, n)
--- //depot/projects/smpng/sys/vm/uma_core.c	2006/01/06 20:21:45
+++ //depot/user/jhb/lock/vm/uma_core.c	2006/01/06 21:17:48
@@ -1789,7 +1789,7 @@
 		   ("malloc(M_WAITOK) in interrupt context"));
 		if (nosleepwithlocks) {
 #ifdef WITNESS
-			badness = WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
+			badness = WITNESS_CHECK(WARN_GIANTOK | WARN_SLEEPOK,
 			    NULL,
 			    "malloc(M_WAITOK) of \"%s\", forcing M_NOWAIT",
 			    zone->uz_name);