Index: amd64/amd64_trap.S
===================================================================
RCS file: /cvsroot/src/sys/arch/amd64/amd64/amd64_trap.S,v
retrieving revision 1.45
diff -p -u -r1.45 amd64_trap.S
--- amd64/amd64_trap.S	12 Aug 2018 06:11:47 -0000	1.45
+++ amd64/amd64_trap.S	6 Nov 2018 00:03:08 -0000
@@ -673,15 +673,20 @@ calltrap:
 #ifdef DIAGNOSTIC
 .Lspl_error:
 	STI(si)
-	movabsq	$4f,%rdi
 	movl	CPUVAR(ILEVEL),%esi
 	movl	%ebx,%edx
-	xorq	%rax,%rax
+	cmpl	$0,_C_LABEL(panicstr)
+	jne	5f			/* avoid crazy logging issues */
+	/*xorq	%rax,%rax*/
+	movabsq	$4f,%rdi
 	call	_C_LABEL(printf)
 	movl	%ebx,%edi
 	call	_C_LABEL(spllower)
 	jmp	.Lalltraps_checkast
+5:	movabsq	$7f,%rdi
+	call	_C_LABEL(panic)
 4:	.asciz	"WARNING: SPL NOT LOWERED ON TRAP EXIT %x %x\n"
+7:	.asciz	"spl not lowered on trap exit while panicking %x %x\n"
 #endif
 END(alltraps)
 
Index: amd64/locore.S
===================================================================
RCS file: /cvsroot/src/sys/arch/amd64/amd64/locore.S,v
retrieving revision 1.174
diff -p -u -r1.174 locore.S
--- amd64/locore.S	12 Aug 2018 15:31:01 -0000	1.174
+++ amd64/locore.S	6 Nov 2018 00:03:08 -0000
@@ -1320,17 +1320,22 @@ ENTRY(handle_syscall)
 #ifdef DIAGNOSTIC
 	/* Report SPL error */
 .Lspl_error:
-	movabsq	$4f,%rdi
 	movl	TF_RAX(%rsp),%esi
 	movl	TF_RDI(%rsp),%edx
 	movl	%ebx,%ecx
 	movl	CPUVAR(ILEVEL),%r8d
-	xorq	%rax,%rax
+	cmpl	$0,_C_LABEL(panicstr)
+	jne	5f
+	movabsq	$4f,%rdi
+	/*xorq	%rax,%rax */
 	call	_C_LABEL(printf)
 	movl	$IPL_NONE,%edi
 	call	_C_LABEL(spllower)
 	jmp	.Lsyscall_checkast
+5:	movabsq	$7f,%rdi
+	call	_C_LABEL(panic)
 4:	.asciz	"WARNING: SPL NOT LOWERED ON SYSCALL %d %d EXIT %x %x\n"
+7:	.asciz	"spl not lowered on syscall %d %d exit %x %x\n"
 #endif
 
 /* AST pending or pmap load needed */