Index: sys/amd64/amd64/fpu.c
===================================================================
--- sys/amd64/amd64/fpu.c
+++ sys/amd64/amd64/fpu.c
@@ -1148,8 +1148,9 @@
 	if (pcb->pcb_save == get_pcb_user_save_pcb(pcb)) {
 		if ((pcb->pcb_flags & PCB_USERFPUINITDONE) != 0) {
 			set_pcb_flags(pcb, PCB_FPUINITDONE);
-			clear_pcb_flags(pcb, PCB_KERNFPU);
-		} else
+			if ((pcb->pcb_flags & PCB_KERNFPU_THR) == 0)
+				clear_pcb_flags(pcb, PCB_KERNFPU);
+		} else if ((pcb->pcb_flags & PCB_KERNFPU_THR) == 0)
 			clear_pcb_flags(pcb, PCB_FPUINITDONE | PCB_KERNFPU);
 	} else {
 		if ((ctx->flags & FPU_KERN_CTX_FPUINITDONE) != 0)
@@ -1172,7 +1173,7 @@
 	    ("mangled pcb_save"));
 	KASSERT(PCB_USER_FPU(curpcb), ("recursive call"));
 
-	set_pcb_flags(curpcb, PCB_KERNFPU);
+	set_pcb_flags(curpcb, PCB_KERNFPU | PCB_KERNFPU_THR);
 	return (0);
 }
 
@@ -1182,7 +1183,7 @@
 
 	if ((curthread->td_pflags & TDP_KTHREAD) == 0)
 		return (0);
-	return ((curpcb->pcb_flags & PCB_KERNFPU) != 0);
+	return ((curpcb->pcb_flags & PCB_KERNFPU_THR) != 0);
 }
 
 /*
Index: sys/amd64/include/pcb.h
===================================================================
--- sys/amd64/include/pcb.h
+++ sys/amd64/include/pcb.h
@@ -84,6 +84,7 @@
 #define	PCB_KERNFPU	0x04	/* kernel uses fpu */
 #define	PCB_FPUINITDONE	0x08	/* fpu state is initialized */
 #define	PCB_USERFPUINITDONE 0x10 /* fpu user state is initialized */
+#define	PCB_KERNFPU_THR	0x20
 #define	PCB_32BIT	0x40	/* process has 32 bit context (segs etc) */
 #define	PCB_FPUNOSAVE	0x80	/* no save area for current FPU ctx */