Index: etc/rc.d/savecore
===================================================================
--- etc/rc.d/savecore
+++ etc/rc.d/savecore
@@ -70,7 +70,7 @@
 	if savecore -C "${dev}" >/dev/null; then
 		savecore ${savecore_flags} ${dumpdir} ${dumpdev}
 		if checkyesno crashinfo_enable; then
-			${crashinfo_program} -d ${dumpdir}
+			${crashinfo_program} -b -d ${dumpdir}
 		fi
 		sync
 	else
Index: usr.sbin/crashinfo/crashinfo.8
===================================================================
--- usr.sbin/crashinfo/crashinfo.8
+++ usr.sbin/crashinfo/crashinfo.8
@@ -27,7 +27,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 28, 2008
+.Dd April 19, 2017
 .Dt CRASHINFO 8
 .Os
 .Sh NAME
@@ -88,6 +88,12 @@
 .Pp
 The options are as follows:
 .Bl -tag -width indent
+.It Fl b
+Run in batch mode.  Write most messages to the
+.Pa core.txt.XX
+file instead of the terminal.  This flag is used when
+.Nm
+is run during boot.
 .It Fl d Ar crashdir
 Specify an alternate core dump directory.
 The default crash dump directory is
Index: usr.sbin/crashinfo/crashinfo.sh
===================================================================
--- usr.sbin/crashinfo/crashinfo.sh
+++ usr.sbin/crashinfo/crashinfo.sh
@@ -31,10 +31,16 @@
 
 usage()
 {
-	echo "usage: crashinfo [-d crashdir] [-n dumpnr] [-k kernel] [core]"
+	echo "usage: crashinfo [-b] [-d crashdir] [-n dumpnr]" \
+		"[-k kernel] [core]"
 	exit 1
 }
 
+gdb_six()
+{
+	$GDB --version | grep -q '^GNU gdb 6\.'
+}
+
 # Run a single gdb command against a kernel file in batch mode.
 # The kernel file is specified as the first argument and the command
 # is given in the remaining arguments.
@@ -44,10 +50,10 @@
 
 	k=$1 ; shift
 
-	if [ -x /usr/local/bin/gdb ]; then
-		/usr/local/bin/gdb -batch -ex "$@" $k
+	if gdb_six; then
+		echo -e "$@" | $GDB -x /dev/stdin -batch $k
 	else
-		echo -e "$@" | /usr/bin/gdb -x /dev/stdin -batch $k
+		$GDB -batch -ex "$@" $k
 	fi
 }
 
@@ -80,12 +86,17 @@
 	done
 }
 
+BATCH=false
 CRASHDIR=/var/crash
 DUMPNR=
+GDB=
 KERNEL=
 
-while getopts "d:n:k:" opt; do
+while getopts "bd:n:k:" opt; do
 	case "$opt" in
+	b)
+		BATCH=true
+		;;
 	d)
 		CRASHDIR=$OPTARG
 		;;
@@ -140,6 +151,28 @@
 FILE=$CRASHDIR/core.txt.$DUMPNR
 HOSTNAME=`hostname`
 
+if $BATCH; then
+	echo "Writing crash summary to $FILE."
+	exec > $FILE 2>&1
+fi
+
+# Try to find gdb in the user's PATH.
+if ! GDB=`which gdb`; then
+	# /usr/local/bin is not in the PATH during boot.
+	if [ -x /usr/local/bin/gdb ]; then
+		GDB=/usr/local/bin/gdb
+	else
+		echo "Please install GDB and run 'crashinfo' again." >&2
+		echo "The easiest way to install GDB is: pkg install gdb" >&2
+		exit 1
+	fi
+fi
+
+# Try to avoid ancient versions of gdb, such as 6.1.1 in the base system.
+if gdb_six && test -x /usr/local/bin/gdb; then
+	GDB=/usr/local/bin/gdb
+fi
+
 if [ ! -e $VMCORE ]; then
 	echo "$VMCORE not found"
 	exit 1
@@ -162,8 +195,6 @@
 	exit 1
 fi
 
-echo "Writing crash summary to $FILE."
-
 umask 077
 
 # Simulate uname
@@ -172,7 +203,10 @@
 version=$(gdb_command $KERNEL 'printf "%s", version' | tr '\t\n' '  ')
 machine=$(gdb_command $KERNEL 'printf "%s", machine')
 
-exec > $FILE 2>&1
+if ! $BATCH; then
+	echo "Writing crash summary to $FILE."
+	exec > $FILE 2>&1
+fi
 
 echo "$HOSTNAME dumped core - see $VMCORE"
 echo