Description of problem:
Stopping volumes and containers is not always completed successfully and can lead to various of very unwanted behavior of MD.

How reproducible:
Almost Always (more likely with faster machines)

Steps to Reproduce:
1. Create IMSM RAID
#mdadm -CR /dev/md/imsm0 -e imsm -n4 /dev/sd[a-d]
#mdadm -CR /dev/md/vol0 -l5 -n4 /dev/sd[a-d]
2. Try to stop all volumens
#mdadm -Ss

Actual results:
"mdadm -Ss" hangs (prompt not returned), two mdadm processes run:
#ps -aux | grep mdadm
root      76003  1.2  0.0   7052   832 pts/0    S+   05:18   0:00 mdadm -Ss
root      76005  1.2  0.0   7052  1052 ?        S    05:18   0:00 /sbin/mdadm -I /dev/md127

#cat /proc/mdstat
Personalities : [raid10] [raid6] [raid5] [raid4]
md127 : inactive sda[3](S) sdb[2](S) sdc[1](S) sdd[0](S)
      12612 blocks super external:imsm

or - in worse scenario - volume without container is assembled in result of this race, container not exists in system (no mdadm process in background):

#cat /proc/mdstat
Personalities : [raid10] [raid6] [raid5] [raid4]
md126 : active raid5 sda[3] sdb[2] sdc[1] sdd[0]
      3145728 blocks super external:/md127/0 level 5, 128k chunk, algorithm 0 [4/4] [UUUU]

After killing hanged mdadms, and started "mdadm -Ss" once more volume is stopped, but after re-assemble - volume is very often failed/degraded/broken. 

Expected results:
All volumes and containers are stopped successfully.
#cat /proc/mdstat
Personalities : [raid10] [raid6] [raid5] [raid4]
unused devices: <none>

All of above problems are caused by part of 65-md-incremental.rules file:
---
# In case the initramfs only started some of the arrays in our container,
# run incremental assembly on the container itself.  Note: we ran mdadm
# on the container in 64-md-raid.rules, and that's how the MD_LEVEL
# environment variable is already set.  If that disappears from the other
# file, we will need to add this line into the middle of the next rule:
#       IMPORT{program}="/sbin/mdadm -D --export $tempnode", \

SUBSYSTEM=="block", ACTION=="add|change", KERNEL=="md*", \
        ENV{MD_LEVEL}=="container", RUN+="/sbin/mdadm -I $env{DEVNAME}"

When stopping all volumes and containers, "change" event is generated for some reason. This event triggers "mdadm -I /dev/md{container}" while it (the container) is during stop procedure and blocks it, or assemble the volume.

This part of udev-rule should be removed.