diff --git a/sys/arm64/arm64/unwind.c b/sys/arm64/arm64/unwind.c
index 470b64c00540..32590da5fc46 100644
--- a/sys/arm64/arm64/unwind.c
+++ b/sys/arm64/arm64/unwind.c
@@ -1,53 +1,54 @@
 /*-
  * Copyright (c) 2015 The FreeBSD Foundation
  *
  * This software was developed by Semihalf under
  * the sponsorship of the FreeBSD Foundation.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 #include <sys/param.h>
 #include <sys/proc.h>
 
 #include <machine/stack.h>
 #include <machine/vmparam.h>
 
 bool
 unwind_frame(struct thread *td, struct unwind_state *frame)
 {
 	uintptr_t fp;
 
 	fp = frame->fp;
 
-	if (!kstack_contains(td, fp, sizeof(uintptr_t) * 2))
+	if (!__is_aligned(fp, sizeof(fp)) ||
+	    !kstack_contains(td, fp, sizeof(fp) * 2))
 		return (false);
 
 	/* FP to previous frame (X29) */
 	frame->fp = ((uintptr_t *)fp)[0];
 	/* LR (X30) */
 	frame->pc = ADDR_MAKE_CANONICAL(((uintptr_t *)fp)[1] - 4);
 
 	return (true);
 }
diff --git a/sys/riscv/riscv/unwind.c b/sys/riscv/riscv/unwind.c
index 9efb1fef9451..175e6423a59c 100644
--- a/sys/riscv/riscv/unwind.c
+++ b/sys/riscv/riscv/unwind.c
@@ -1,58 +1,59 @@
 /*-
  * Copyright (c) 2016 Ruslan Bukin <br@bsdpad.com>
  * All rights reserved.
  *
  * Portions of this software were developed by SRI International and the
  * University of Cambridge Computer Laboratory under DARPA/AFRL contract
  * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
  *
  * Portions of this software were developed by the University of Cambridge
  * Computer Laboratory as part of the CTSRD Project, with support from the
  * UK Higher Education Innovation Fund (HEIF).
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 #include <sys/param.h>
 #include <sys/proc.h>
 
 #include <machine/stack.h>
 #include <machine/vmparam.h>
 
 bool
 unwind_frame(struct thread *td, struct unwind_state *frame)
 {
 	uintptr_t fp;
 
 	fp = frame->fp;
 
-	if (!kstack_contains(td, fp - sizeof(fp) * 2, sizeof(fp) * 2))
+	if (!__is_aligned(fp, sizeof(fp)) ||
+	    !kstack_contains(td, fp - sizeof(fp) * 2, sizeof(fp) * 2))
 		return (false);
 
 	frame->sp = fp;
 	frame->fp = ((uintptr_t *)fp)[-2];
 	frame->pc = ((uintptr_t *)fp)[-1] - 4;
 
 	return (true);
 }