diff --git a/external/cddl/osnet/dev/dtrace/aarch64/dtrace_subr.c b/external/cddl/osnet/dev/dtrace/aarch64/dtrace_subr.c
index 7a968c9c2ecc..56772b99b878 100644
--- a/external/cddl/osnet/dev/dtrace/aarch64/dtrace_subr.c
+++ b/external/cddl/osnet/dev/dtrace/aarch64/dtrace_subr.c
@@ -292,7 +292,7 @@ dtrace_invop_start(struct trapframe *frame)
 				sp += (offs);
 			break;
 		default:
-			break;
+			__unreachable();
 		}
 
 		/* Update the stack pointer and program counter to continue */
diff --git a/external/cddl/osnet/dev/fbt/aarch64/fbt_isa.c b/external/cddl/osnet/dev/fbt/aarch64/fbt_isa.c
index 123290616ec5..54f851925f04 100644
--- a/external/cddl/osnet/dev/fbt/aarch64/fbt_isa.c
+++ b/external/cddl/osnet/dev/fbt/aarch64/fbt_isa.c
@@ -36,6 +36,9 @@
 #include <sys/cpu.h>
 #include <sys/module.h>
 #include <sys/kmem.h>
+
+#include <ddb/ddb.h>
+
 #include <machine/cpufunc.h>
 
 #include <sys/dtrace.h>
@@ -67,6 +70,7 @@ fbt_invop(uintptr_t addr, struct trapframe *frame, uintptr_t rval)
 			    frame->tf_regs.r_reg[3], frame->tf_regs.r_reg[4]);
 
 			cpu->cpu_dtrace_caller = 0;
+			KASSERT(fbt->fbtp_savedval != 0);
 			return (fbt->fbtp_savedval);
 		}
 	}
@@ -78,8 +82,9 @@ void
 fbt_patch_tracepoint(fbt_probe_t *fbt, fbt_patchval_t val)
 {
 
-	*fbt->fbtp_patchpoint = val;
-	cpu_icache_sync_range((vm_offset_t)fbt->fbtp_patchpoint, 4);
+	db_write_bytes((db_addr_t)fbt->fbtp_patchpoint, sizeof(val),
+	    (const void *)&val);
+	cpu_icache_sync_range((vm_offset_t)fbt->fbtp_patchpoint, sizeof(val));
 }
 
 #if defined(__FreeBSD__)
@@ -138,6 +143,7 @@ fbt_provide_module_cb(const char *name, int symindx, void *value,
 
 	if (instr >= limit)
 		return (0);
+	KASSERT(*instr != 0);
 
 #ifdef __FreeBSD__
 	fbt = malloc(sizeof (fbt_probe_t), M_FBT, M_WAITOK | M_ZERO);
@@ -157,7 +163,6 @@ fbt_provide_module_cb(const char *name, int symindx, void *value,
 #endif
 	fbt->fbtp_savedval = *instr;
 	fbt->fbtp_patchval = FBT_PATCHVAL;
-	fbt->fbtp_rval = DTRACE_INVOP_PUSHM;
 	fbt->fbtp_symindx = symindx;
 
 	fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)];
@@ -188,6 +193,7 @@ again:
 
 	if (instr >= limit)
 		return (0);
+	KASSERT(*instr != 0);
 
 	/*
 	 * We have a winner!
@@ -215,13 +221,10 @@ again:
 #ifdef __NetBSD__
 	fbt->fbtp_ctl = mod;
 #endif
-	fbt->fbtp_symindx = symindx;
-	if ((*instr & B_MASK) == B_INSTR)
-		fbt->fbtp_rval = DTRACE_INVOP_B;
-	else
-		fbt->fbtp_rval = DTRACE_INVOP_RET;
 	fbt->fbtp_savedval = *instr;
 	fbt->fbtp_patchval = FBT_PATCHVAL;
+	fbt->fbtp_symindx = symindx;
+
 	fbt->fbtp_hashnext = fbt_probetab[FBT_ADDR2NDX(instr)];
 	fbt_probetab[FBT_ADDR2NDX(instr)] = fbt;
 
diff --git a/sys/arch/aarch64/aarch64/vectors.S b/sys/arch/aarch64/aarch64/vectors.S
index de3c6654f126..d91e61b23132 100644
--- a/sys/arch/aarch64/aarch64/vectors.S
+++ b/sys/arch/aarch64/aarch64/vectors.S
@@ -3,6 +3,18 @@
 #include <aarch64/asm.h>
 #include "assym.h"
 #include "opt_ddb.h"
+#include "opt_dtrace.h"
+
+#ifdef KDTRACE_HOOKS
+/*
+ * dtrace needs to emulate  stp x29,x30,[sp,#-FRAMESIZE],  and
+ * FRAMESIZE can be as large as 512, so create a 512-byte buffer
+ * between the interrupted code's frame and our struct trapframe.
+ */
+#define	TRAP_FRAMESIZE	(TF_SIZE + 512)
+#else
+#define	TRAP_FRAMESIZE	TF_SIZE
+#endif
 
 	/*
 	 * vector_entry macro must be small enough to fit 0x80 bytes!
@@ -11,7 +23,7 @@
 	.align 7	/* aligned 0x80 */
 
 	.if \el == 1
-	sub	sp, sp, #TF_SIZE	/* need to allocate stack on el1 */
+	sub	sp, sp, #TRAP_FRAMESIZE	/* need to allocate stack on el1 */
 	.endif
 
 	stp	x0, x1, [sp, #TF_X0]
@@ -35,7 +47,7 @@
 	.if \el == 0
 	mrs	x20, sp_el0
 	.else
-	add	x20, sp, #TF_SIZE	/* sp is already adjusted */
+	add	x20, sp, #TRAP_FRAMESIZE	/* sp is already adjusted */
 	.endif
 	mrs	x21, elr_el1