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
+
+ fio_jobs=""
+ cnt=0
+ for sd in $disks; do
+ cnt=$((cnt+1))
+ fio_jobs=$fio_jobs" --name=job1 --filename=$sd: "
+ dev_name=$(basename "$sd")
+ q_path=/sys/block/$dev_name/queue
+
+ sched_idx=$((cnt % ${#scheds[@]}))
+ echo "${scheds[$sched_idx]}" > "$q_path/scheduler"
+ echo $cnt > "$q_path/../device/queue_depth"
+ done
+
+ fio --rw=randread --size=128G --direct=1 --ioengine=libaio \
+ --iodepth=2048 --numjobs=$nr_fio_jobs --bs=4k \
+ --group_reporting=1 --group_reporting=1 --runtime=$runtime \
+ --loops=10000 "$fio_jobs" > "$FULL" 2>&1 &
+
+ sleep 7
+ for sd in $disks; do
+ dev_name=$(basename "$sd")
+ dpath=/sys/block/$dev_name/device
+ [ -f "$dpath/delete" ] && echo 1 > "$dpath/delete"
+ done
+
+ wait
+}
+
+
+test() {
+ echo "Running ${TEST_NAME}"
+
+ scsi_debug_stress_remove
+
+ echo "Test complete"
+}
diff --git a/tests/block/022.out b/tests/block/022.out
new file mode 100644
index 0000000..14d43cb
--- /dev/null
+++ b/tests/block/022.out
@@ -0,0 +1,2 @@
+Running block/022
+Test complete
--
2.17.1
