Index: head/sys/amd64/include/gdb_machdep.h
===================================================================
--- head/sys/amd64/include/gdb_machdep.h	(revision 351368)
+++ head/sys/amd64/include/gdb_machdep.h	(revision 351369)
@@ -1,56 +1,57 @@
 /*-
  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
  *
  * Copyright (c) 2004 Marcel Moolenaar
  * All rights reserved.
  *
  * 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 ``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 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.
  *
  * $FreeBSD$
  */
 
 #ifndef _MACHINE_GDB_MACHDEP_H_
 #define	_MACHINE_GDB_MACHDEP_H_
 
-#define	GDB_BUFSZ	(GDB_NREGS * 16)
+#define	GDB_BUFSZ	4096
 #define	GDB_NREGS	56
 #define	GDB_REG_PC	16
+_Static_assert(GDB_BUFSZ >= (GDB_NREGS * 16), "buffer fits 'g' regs");
 
 static __inline size_t
 gdb_cpu_regsz(int regnum)
 {
 	return ((regnum > 16 && regnum < 24) ? 4 : 8);
 }
 
 static __inline int
 gdb_cpu_query(void)
 {
 	return (0);
 }
 
 void *gdb_begin_write(void);
 void *gdb_cpu_getreg(int, size_t *);
 void gdb_cpu_setreg(int, void *);
 int gdb_cpu_signal(int, int);
 void gdb_end_write(void *);
 
 #endif /* !_MACHINE_GDB_MACHDEP_H_ */