new file mode 100644
@@ -0,0 +1,147 @@
+#! /bin/bash
+# FS QA Test 411
+#
+# This test cover linux commit 7ae8fd0, kernel two mnt_group_id == 0
+# (no peer)vfsmount as peers. It case kernel dereference a NULL
+# address.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2016 Red Hat Inc. All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it would be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write the Free Software Foundation,
+# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+#-----------------------------------------------------------------------
+#
+
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1 # failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+ cd /
+ rm -f $tmp.*
+ _clear_mount_stack
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+_supported_fs generic
+_supported_os Linux
+_require_scratch
+_require_test
+
+fs_stress()
+{
+ local target=$1
+
+ $FSSTRESS_PROG -z -n 500 -p 5 \
+ -f creat=5 \
+ -f mkdir=5 \
+ -f dwrite=1 \
+ -f dread=1 \
+ -f link=2 \
+ -f rename=1 \
+ -f rmdir=2 \
+ -f unlink=1 \
+ -f symlink=1 \
+ -f write=1 \
+ -f read=1 \
+ -f chown=1 \
+ -f getdents=1 \
+ -f fiemap=1 \
+ -d $target >/dev/null
+ sync
+}
+
+# prepare some mountpoint dir
+MNTHEAD=$TEST_DIR/$seq
+mkdir $MNTHEAD 2>>$seqres.full
+mpA=$MNTHEAD/"$$"_mpA
+mpB=$MNTHEAD/"$$"_mpB
+mpC=$MNTHEAD/"$$"_mpC
+
+find_mnt()
+{
+ echo "------"
+ findmnt -n -o TARGET,SOURCE $SCRATCH_DEV | \
+ sed -e "s;$mpA;mpA;g" \
+ -e "s;$mpB;mpB;g" \
+ -e "s;$mpC;mpC;g" | \
+ _filter_spaces | _filter_scratch | \
+ _filter_test_dir | sort
+ echo "======"
+}
+
+start_test()
+{
+ local type=$1
+
+ _get_mount $SCRATCH_DEV $MNTHEAD
+ mount --make-"${type}" $MNTHEAD
+ rm -rf $mpA $mpB $mpC 2>/dev/null
+ mkdir $mpA $mpB $mpC
+ _scratch_mkfs >$seqres.full 2>&1
+}
+
+end_test()
+{
+ rm -rf $mpA $mpB $mpC 2>/dev/null
+ _clear_mount_stack
+}
+
+#
+# shared New FS shared
+# -----------------------[A/mnt1]----------------------
+# | | |
+# | bind | bind | New FS
+# [C/mnt1]--[slave C]<------[shared A]------>[slave B]--[B/mnt1]--[B/mnt1/mnt2]
+#
+crash_test()
+{
+ start_test shared
+
+ _get_mount $SCRATCH_DEV $mpA
+ mkdir $mpA/mnt1
+ mount --make-shared $mpA
+ _get_mount --bind $mpA $mpB
+ _get_mount --bind $mpA $mpC
+ mount --make-slave $mpB
+ mount --make-slave $mpC
+ _get_mount $SCRATCH_DEV $mpA/mnt1
+ mkdir $mpA/mnt1/mnt2
+
+ _get_mount $SCRATCH_DEV $mpB/mnt1/mnt2
+ find_mnt
+ fs_stress $mpB/mnt1/mnt2
+
+ end_test
+ echo "crash test passed"
+}
+
+crash_test
+
+# success, all done
+status=0
+exit
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@@ -0,0 +1,12 @@
+QA output created by 411
+------
+TEST_DIR/411 SCRATCH_DEV
+mpA SCRATCH_DEV
+mpA/mnt1 SCRATCH_DEV
+mpB SCRATCH_DEV
+mpB/mnt1 SCRATCH_DEV
+mpB/mnt1/mnt2 SCRATCH_DEV
+mpC SCRATCH_DEV
+mpC/mnt1 SCRATCH_DEV
+======
+crash test passed
@@ -413,3 +413,4 @@
408 auto quick clone dedupe metadata
409 auto quick mount
410 auto quick mount
+411 auto quick mount