udevルールは実行されますが、すべての実行コマンドは失敗します。

Raspberry PiでRaspian（Debian）Stretchを使用中に奇妙なudev問題が発生しました。 USBフラッシュドライブが接続されたときに実行される単純なudevルールは次のとおりです。

# /etc/udev/rules.d/70-usb-test.rules
KERNEL=="sd?1", SUBSYSTEMS=="usb", RUN+="/opt/bin/usb-test.sh"
KERNEL=="sd?1", SUBSYSTEMS=="usb", SYMLINK+="usb-test"

内容/opt/bin/usb-test.sh（スクリプトは実行可能としてマークされています）：

#!/bin/bash
date >> /var/log/usb-test.log

シンボリックリンクは作成されますが、/dev/usb-testファイルは作成されません/var/log/usb-test.log。

これは次の出力ですtail /var/log/syslog。

Oct 30 15:24:02 raspberrypi kernel: [ 9382.740128] scsi 2:0:0:0: Direct-Access                               0.00 PQ: 0 ANSI: 2
Oct 30 15:24:02 raspberrypi kernel: [ 9382.747435] sd 2:0:0:0: Attached scsi generic sg2 type 0
Oct 30 15:24:02 raspberrypi kernel: [ 9382.748278] sd 2:0:0:0: [sdc] 15794176 512-byte logical blocks: (8.09 GB/7.53 GiB)
Oct 30 15:24:02 raspberrypi kernel: [ 9382.748810] sd 2:0:0:0: [sdc] Write Protect is off
Oct 30 15:24:02 raspberrypi kernel: [ 9382.748827] sd 2:0:0:0: [sdc] Mode Sense: 00 00 00 00
Oct 30 15:24:02 raspberrypi kernel: [ 9382.749235] sd 2:0:0:0: [sdc] Asking for cache data failed
Oct 30 15:24:02 raspberrypi kernel: [ 9382.749247] sd 2:0:0:0: [sdc] Assuming drive cache: write through
Oct 30 15:24:02 raspberrypi kernel: [ 9382.909187]  sdc: sdc1
Oct 30 15:24:02 raspberrypi kernel: [ 9382.913033] sd 2:0:0:0: [sdc] Attached SCSI removable disk
Oct 30 15:24:03 raspberrypi systemd-udevd[3853]: Process '/opt/bin/usb-test.sh' failed with exit code 1.

lsusb:

$ lsusb
Bus 001 Device 005: ID 20a0:0006 Clay Logic 
Bus 001 Device 011: ID 1307:0165 Transcend Information, Inc. 2GB/4GB/8GB Flash Drive
Bus 001 Device 006: ID 0480:a009 Toshiba America Inc Stor.E Basics
Bus 001 Device 009: ID 0480:a202 Toshiba America Inc Canvio Basics HDD
Bus 001 Device 004: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp. SMC9514 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

udevadmモニター：

$ udevadm monitor
monitor will print the received events for:
UDEV - the event which udev sends out after rule processing
KERNEL - the kernel uevent

KERNEL[9851.384334] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3 (usb)
KERNEL[9851.402507] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0 (usb)
KERNEL[9851.418037] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2 (scsi)
KERNEL[9851.418582] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/scsi_host/host2 (scsi_host)
UDEV  [9851.545506] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3 (usb)
UDEV  [9851.570276] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0 (usb)
UDEV  [9851.593606] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2 (scsi)
UDEV  [9851.615895] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/scsi_host/host2 (scsi_host)
KERNEL[9852.486019] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0 (scsi)
KERNEL[9852.486271] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0/2:0:0:0 (scsi)
KERNEL[9852.486448] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0/2:0:0:0/scsi_disk/2:0:0:0 (scsi_disk)
KERNEL[9852.486620] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0/2:0:0:0/scsi_device/2:0:0:0 (scsi_device)
KERNEL[9852.494568] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0/2:0:0:0/scsi_generic/sg2 (scsi_generic)
KERNEL[9852.496172] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0/2:0:0:0/bsg/2:0:0:0 (bsg)
KERNEL[9852.498091] add      /devices/virtual/bdi/8:32 (bdi)
UDEV  [9852.549816] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0 (scsi)
UDEV  [9852.560113] add      /devices/virtual/bdi/8:32 (bdi)
UDEV  [9852.590072] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0/2:0:0:0 (scsi)
KERNEL[9852.659280] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0/2:0:0:0/block/sdc (block)
KERNEL[9852.659644] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0/2:0:0:0/block/sdc/sdc1 (block)
UDEV  [9852.679376] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0/2:0:0:0/scsi_disk/2:0:0:0 (scsi_disk)
UDEV  [9852.726897] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0/2:0:0:0/scsi_device/2:0:0:0 (scsi_device)
UDEV  [9852.741386] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0/2:0:0:0/bsg/2:0:0:0 (bsg)
UDEV  [9852.745223] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0/2:0:0:0/scsi_generic/sg2 (scsi_generic)
UDEV  [9853.032330] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0/2:0:0:0/block/sdc (block)
UDEV  [9853.256996] add      /devices/platform/soc/20980000.usb/usb1/1-1/1-1.3/1-1.3.3/1-1.3.3:1.0/host2/target2:0:0/2:0:0:0/block/sdc/sdc1 (block)

何が起こっているのか知っている人はいますか？