On Thu, Dec 13, 2018 at 09:24:09AM +0800, Ming Lei wrote:
> On Wed, Dec 12, 2018 at 06:09:59PM -0500, Dennis Zhou wrote:
> > This test exposed a race condition with shutting down a request_queue
> > and the new blkg association. The issue ended up being that while the
> > request_queue will just start failing requests, blkg destruction sets
> > the q->root_blkg to %NULL. This caused a NPE when trying to reference
> > it. So to help prevent this from happening again, integrate Ming's test
> > into blktests so that it can more easily be ran.
> >
> > Signed-off-by: Dennis Zhou <dennis@xxxxxxxxxx>
> > Cc: Ming Lei <ming.lei@xxxxxxxxxx>
> > ---
> > tests/block/022 | 96 +++++++++++++++++++++++++++++++++++++++++++++
> > tests/block/022.out | 2 +
> > 2 files changed, 98 insertions(+)
> > create mode 100755 tests/block/022
> > create mode 100644 tests/block/022.out
> >
> > diff --git a/tests/block/022 b/tests/block/022
> > new file mode 100755
> > index 0000000..45bfff7
> > --- /dev/null
> > +++ b/tests/block/022
> > @@ -0,0 +1,96 @@
> > +#!/bin/bash
> > +# SPDX-License-Identifier: GPL-3.0+
> > +# Copyright (C) 2018 Ming Lei
> > +#
> > +# Regression test for patch "blkcg: handle dying request_queue when associating
> > +# a blkg"
> > +#
> > +# This tries to expose the race condition between blkg association and
> > +# request_queue shutdown. When a request_queue is shutdown, the corresponding
> > +# blkgs are destroyed. Any further associations should fail gracefully and not
> > +# cause a kernel panic.
> > +
> > +. tests/block/rc
> > +. common/scsi_debug
> > +. common/cgroup
> > +
> > +DESCRIPTION="test graceful shutdown of scsi_debug devices with running fio jobs"
> > +QUICK=1
> > +
> > +requires() {
> > + _have_cgroup2_controller io && _have_scsi_debug && _have_fio
> > +}
> > +
> > +scsi_debug_stress_remove() {
> > + scsi_debug_path="/sys/bus/pseudo/drivers/scsi_debug"
> > + count=21
> > +
> > + runtime=12
> > + nr_fio_jobs=8
> > + scsi_dbg_ndelay=10000
> > +
> > + # set higher aio limit
> > + echo 524288 > /proc/sys/fs/aio-max-nr
> > +
> > + #figure out the CAN_QUEUE
> > + can_queue=$(((count + 1) * (count / 2) / 2))
> > +
> > + rmmod scsi_debug > /dev/null 2>&1
> > + modprobe scsi_debug virtual_gb=128 max_luns=$count \
> > + ndelay=$scsi_dbg_ndelay max_queue=$can_queue
> > +
> > + # figure out scsi_debug disks
> > + hosts=$(ls -d /sys/bus/pseudo/drivers/scsi_debug/adapter0/host*)
> > + hostname=$(basename "$hosts")
> > + host=$(echo "$hostname" | grep -o -E '[0-9]+')
> > +
> > + sdisks=$(ls -d $scsi_debug_path/adapter*/"$hostname"/target*/*/block/*)
> > + disks=""
> > + for sd in $sdisks; do
> > + disks+="/dev/"$(basename "$sd")
> > + disks+=" "
> > + done
> > +
> > + use_mq=$(cat /sys/module/scsi_mod/parameters/use_blk_mq)
> > + if [[ $use_mq = "Y" ]]; then
> > + scheds=("none" "mq-deadline" "kyber")
> > + else
> > + scheds=("noop" "deadline" "cfq")
> > + fi
>
> You may use the following to figure out all supported io schedulers,
> especially we have removed all legacy io schedulers.
>
> IOSCHEDS=`sed 's/[][]//g' $Q_PATH/scheduler`
>
>
> Thanks,
> Ming
Thanks Ming! I'll post a v2 update for this patch.
Thanks,
Dennis
