diff --git a/sys/cddl/dev/fbt/x86/fbt_isa.c b/sys/cddl/dev/fbt/x86/fbt_isa.c
--- a/sys/cddl/dev/fbt/x86/fbt_isa.c
+++ b/sys/cddl/dev/fbt/x86/fbt_isa.c
@@ -57,6 +57,8 @@
 #define	FBT_PATCHVAL		0xf0
 #endif
 
+#define FBT_AFRAMES 2
+
 int
 fbt_invop(uintptr_t addr, struct trapframe *frame, uintptr_t scratch __unused)
 {
@@ -234,7 +236,7 @@
 	fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO);
 	fbt->fbtp_name = name;
 	fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
-	    name, FBT_ENTRY, 3, fbt);
+	    name, FBT_ENTRY, FBT_AFRAMES, fbt);
 	fbt->fbtp_patchpoint = instr;
 	fbt->fbtp_ctl = lf;
 	fbt->fbtp_loadcnt = lf->loadcnt;
@@ -328,7 +330,7 @@
 
 	if (retfbt == NULL) {
 		fbt->fbtp_id = dtrace_probe_create(fbt_id, modname,
-		    name, FBT_RETURN, 3, fbt);
+		    name, FBT_RETURN, FBT_AFRAMES, fbt);
 	} else {
 		retfbt->fbtp_probenext = fbt;
 		fbt->fbtp_id = retfbt->fbtp_id;