On Wed, Apr 01, 2015 at 01:56:09PM -0400, Brian Foster wrote:
> On Wed, Apr 01, 2015 at 09:53:25PM +0800, Eryu Guan wrote:
> > Exercise fs freeze/unfreeze and mount/umount race, which could lead to
> > use-after-free oops.
> >
> > This commit fixed the issue:
> > 1494583 fix get_active_super()/umount() race
> >
> > This test case is based on a script from Monakhov Dmitriy.
> >
> > Signed-off-by: Eryu Guan <eguan@xxxxxxxxxx>
> > ---
> > v2:
> > - add comments to explain dmsetup is used not xfs_freeze to freeze filesystem
> > - detect failures in setup phase, so test exits not continus with errors
> >
> > tests/generic/080 | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++
> > tests/generic/080.out | 2 +
> > tests/generic/group | 1 +
> > 3 files changed, 105 insertions(+)
> > create mode 100755 tests/generic/080
> > create mode 100644 tests/generic/080.out
> >
> > diff --git a/tests/generic/080 b/tests/generic/080
> > new file mode 100755
> > index 0000000..fd460b1
> > --- /dev/null
> > +++ b/tests/generic/080
> > @@ -0,0 +1,102 @@
> > +#! /bin/bash
> > +# FS QA Test No. 080
> > +#
> > +# Exercise fs freeze/unfreeze and mount/umount race, which could lead to
> > +# use-after-free oops.
> > +#
> > +# This commit fixed the issue:
> > +# 1494583 fix get_active_super()/umount() race
> > +#
> > +#-----------------------------------------------------------------------
> > +# Copyright (c) 2015 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.*
> > + cleanup_dmdev
> > +}
> > +
> > +# get standard environment, filters and checks
> > +. ./common/rc
> > +. ./common/filter
> > +
> > +# real QA test starts here
> > +_supported_fs generic
> > +_supported_os Linux
> > +_require_scratch
> > +_require_block_device $SCRATCH_DEV
> > +_require_command $DMSETUP_PROG
> > +_require_freeze
> > +
> > +setup_dmdev()
> > +{
> > + table="0 $size_in_sector linear $SCRATCH_DEV 0"
> > + $DMSETUP_PROG create $node --table "$table" >>$seqres.full 2>&1 && \
> > + $DMSETUP_PROG mknodes >/dev/null 2>&1
> > + return $?
> > +}
> > +
> > +cleanup_dmdev()
> > +{
> > + # in case it's still suspended and/or mounted
> > + $DMSETUP_PROG resume $lvdev >/dev/null 2>&1
> > + $UMOUNT_PROG $lvdev >/dev/null 2>&1
> > +
> > + $DMSETUP_PROG remove $node >>$seqres.full 2>&1
> > + $DMSETUP_PROG mknodes >/dev/null 2>&1
> > +}
> > +
> > +rm -f $seqres.full
> > +echo "Silence is golden"
> > +
> > +size=$((256 * 1024 * 1024))
> > +size_in_sector=$((size / 512))
> > +_scratch_mkfs_sized $size >>$seqres.full 2>&1
> > +
> > +node=$seq-test
> > +lvdev=/dev/mapper/$node
> > +setup_dmdev || _fail "setup dm device failed"
> > +
> > +# take use of dmsetup suspend to freeze the fs.
> > +# xfs_freeze/fsfreeze cannot be used in this test, because it can possibly
> > +# freeze the root fs of the host when SCRATCH_MNT is not mounted
> > +for ((i=0; i<100; i++)); do
> > + $DMSETUP_PROG suspend $lvdev >/dev/null 2>&1
> > + $DMSETUP_PROG resume $lvdev >/dev/null 2>&1
> > +done &
> > +pid=$!
> > +for ((i=0; i<100; i++)); do
> > + $MOUNT_PROG $lvdev $SCRATCH_MNT >/dev/null 2>&1
> > + $UMOUNT_PROG $lvdev >/dev/null 2>&1
> > +done &
> > +pid="$pid $!"
> > +
>
> Still need error checks for the suspend/resume and mount/umount
> commands. As it is, I reproduce mount errors if I add such checking to
> this test. That needs to be either addressed or documented, if
> expected..?
I don't expect these racing commands to succeed all the time, and the
results are not important either, as long as they are racing with each
other.
I think I can add some comments to state the fact.
Thanks for your review!
Eryu
>
> My primary concern is that as written, any or all of these commands
> could fail/explode for whatever external reason and the test will just
> silently pass. :)
>
> Brian
>
> > +wait $pid
> > +
> > +status=0
> > +exit
> > diff --git a/tests/generic/080.out b/tests/generic/080.out
> > new file mode 100644
> > index 0000000..11a4a1a
> > --- /dev/null
> > +++ b/tests/generic/080.out
> > @@ -0,0 +1,2 @@
> > +QA output created by 080
> > +Silence is golden
> > diff --git a/tests/generic/group b/tests/generic/group
> > index ee5b642..cf7408c 100644
> > --- a/tests/generic/group
> > +++ b/tests/generic/group
> > @@ -82,6 +82,7 @@
> > 077 acl attr auto enospc
> > 078 auto quick metadata
> > 079 acl attr ioctl metadata auto quick
> > +080 auto freeze mount
> > 083 rw auto enospc stress
> > 088 perms auto quick
> > 089 metadata auto
> > --
> > 2.1.0
> >
> > --
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