From ca162c0888aa9eee9cc079f2be02efafc4b6d9f0 Mon Sep 17 00:00:00 2001
From: Robert Watson <rwatson@FreeBSD.org>
Date: Thu, 5 Mar 2015 07:40:41 +0000
Subject: [PATCH] Don't all DTrace's FBT on ARM to instrument
 undefinedinstruction(), as this would lead to DTrace reentrance.

Sponsored by:	DARPA, AFRL
---
 sys/cddl/dev/fbt/arm/fbt_isa.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/sys/cddl/dev/fbt/arm/fbt_isa.c b/sys/cddl/dev/fbt/arm/fbt_isa.c
index 99fe067cd0ad..c6bc0f04ea10 100644
--- a/sys/cddl/dev/fbt/arm/fbt_isa.c
+++ b/sys/cddl/dev/fbt/arm/fbt_isa.c
@@ -105,6 +105,13 @@ fbt_provide_module_function(linker_file_t lf, int symindx,
 	if (name[0] == '_' && name[1] == '_')
 		return (0);
 
+	/*
+	 * Architecture-specific exclusion list, largely to do with FBT trap
+	 * processing, to prevent reentrance.
+	 */
+	if (strcmp(name, "undefinedinstruction") == 0)
+		return (0);
+
 	instr = (uint32_t *)symval->value;
 	limit = (uint32_t *)(symval->value + symval->size);