Bug#765780: systemd: "systemd-udevd blocked" journal message when writing ISO to USB stick

[Scott Leggett]

Package: systemd
Version: 215-5+b1
Severity: normal

Dear Maintainer,

   Writing an ISO to a USB stick caused this message to appear in the
   journal multiple times. Despite this, the image was written
   successfully.

   I would not expect such a common operation to cause this kind of
   scary message to be logged.

-- Log snippet

Oct 17 22:56:56 whist kernel:       Tainted: G           O  3.16-2-amd64 #1
Oct 17 22:56:56 whist kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Oct 17 22:56:56 whist kernel: systemd-udevd   D ffff88003686c528     0   313      1 0x00000000
Oct 17 22:56:56 whist kernel:  ffff88003686c0d0 0000000000000086 0000000000014240 ffff88040ce6ffd8
Oct 17 22:56:56 whist kernel:  0000000000014240 ffff88003686c0d0 ffff88040d5951d8 ffff88040ce6fbe0
Oct 17 22:56:56 whist kernel:  ffff88040d5951dc ffff88003686c0d0 00000000ffffffff ffff88040d5951e0
Oct 17 22:56:56 whist kernel: Call Trace:
Oct 17 22:56:56 whist kernel:  [<ffffffff81508e35>] ? schedule_preempt_disabled+0x25/0x70
Oct 17 22:56:56 whist kernel:  [<ffffffff8150a8f3>] ? __mutex_lock_slowpath+0xd3/0x1c0
Oct 17 22:56:56 whist kernel:  [<ffffffff8150a9fb>] ? mutex_lock+0x1b/0x2a
Oct 17 22:56:56 whist kernel:  [<ffffffff811d9733>] ? __blkdev_get+0x63/0x480
Oct 17 22:56:56 whist kernel:  [<ffffffff811d9ea0>] ? blkdev_get_by_dev+0x40/0x40
Oct 17 22:56:56 whist kernel:  [<ffffffff811d9d06>] ? blkdev_get+0x1b6/0x310
Oct 17 22:56:56 whist kernel:  [<ffffffff811d9ea0>] ? blkdev_get_by_dev+0x40/0x40
Oct 17 22:56:56 whist kernel:  [<ffffffff811a2ce2>] ? do_dentry_open+0x1f2/0x330
Oct 17 22:56:56 whist kernel:  [<ffffffff811a2fed>] ? finish_open+0x2d/0x40
Oct 17 22:56:56 whist kernel:  [<ffffffff811b3aca>] ? do_last+0xa5a/0x11e0
Oct 17 22:56:56 whist kernel:  [<ffffffff811afef1>] ? link_path_walk+0x71/0x890
Oct 17 22:56:56 whist kernel:  [<ffffffff811b430b>] ? path_openat+0xbb/0x680
Oct 17 22:56:56 whist kernel:  [<ffffffff81177835>] ? free_pages_and_swap_cache+0x95/0xb0
Oct 17 22:56:56 whist kernel:  [<ffffffff811b507a>] ? do_filp_open+0x3a/0x90
Oct 17 22:56:56 whist kernel:  [<ffffffff811c10ac>] ? __alloc_fd+0x7c/0x120
Oct 17 22:56:56 whist kernel:  [<ffffffff811a4529>] ? do_sys_open+0x129/0x220
Oct 17 22:56:56 whist kernel:  [<ffffffff8150c26d>] ? system_call_fast_compare_end+0x10/0x15
Oct 17 22:58:56 whist kernel: INFO: task systemd-udevd:313 blocked for more than 120 seconds.
Oct 17 22:58:56 whist kernel:       Tainted: G           O  3.16-2-amd64 #1
Oct 17 22:58:56 whist kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Oct 17 22:58:56 whist kernel: systemd-udevd   D ffff88003686c528     0   313      1 0x00000000
Oct 17 22:58:56 whist kernel:  ffff88003686c0d0 0000000000000086 0000000000014240 ffff88040ce6ffd8
Oct 17 22:58:56 whist kernel:  0000000000014240 ffff88003686c0d0 ffff88040d5951d8 ffff88040ce6fbe0
Oct 17 22:58:56 whist kernel:  ffff88040d5951dc ffff88003686c0d0 00000000ffffffff ffff88040d5951e0
Oct 17 22:58:56 whist kernel: Call Trace:
Oct 17 22:58:56 whist kernel:  [<ffffffff81508e35>] ? schedule_preempt_disabled+0x25/0x70
Oct 17 22:58:56 whist kernel:  [<ffffffff8150a8f3>] ? __mutex_lock_slowpath+0xd3/0x1c0
Oct 17 22:58:56 whist kernel:  [<ffffffff8150a9fb>] ? mutex_lock+0x1b/0x2a
Oct 17 22:58:56 whist kernel:  [<ffffffff811d9733>] ? __blkdev_get+0x63/0x480
Oct 17 22:58:56 whist kernel:  [<ffffffff811d9ea0>] ? blkdev_get_by_dev+0x40/0x40
Oct 17 22:58:56 whist kernel:  [<ffffffff811d9d06>] ? blkdev_get+0x1b6/0x310
Oct 17 22:58:56 whist kernel:  [<ffffffff811d9ea0>] ? blkdev_get_by_dev+0x40/0x40
Oct 17 22:58:56 whist kernel:  [<ffffffff811a2ce2>] ? do_dentry_open+0x1f2/0x330
Oct 17 22:58:56 whist kernel:  [<ffffffff811a2fed>] ? finish_open+0x2d/0x40
Oct 17 22:58:56 whist kernel:  [<ffffffff811b3aca>] ? do_last+0xa5a/0x11e0
Oct 17 22:58:56 whist kernel:  [<ffffffff811afef1>] ? link_path_walk+0x71/0x890
Oct 17 22:58:56 whist kernel:  [<ffffffff811b430b>] ? path_openat+0xbb/0x680
Oct 17 22:58:56 whist kernel:  [<ffffffff81177835>] ? free_pages_and_swap_cache+0x95/0xb0
Oct 17 22:58:56 whist kernel:  [<ffffffff811b507a>] ? do_filp_open+0x3a/0x90
Oct 17 22:58:56 whist kernel:  [<ffffffff811c10ac>] ? __alloc_fd+0x7c/0x120
Oct 17 22:58:56 whist kernel:  [<ffffffff811a4529>] ? do_sys_open+0x129/0x220
Oct 17 22:58:56 whist kernel:  [<ffffffff8150c26d>] ? system_call_fast_compare_end+0x10/0x15

-- Package-specific info:

-- System Information:
Debian Release: jessie/sid
  APT prefers testing-updates
  APT policy: (500, 'testing-updates'), (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 3.16-2-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_AU.UTF-8, LC_CTYPE=en_AU.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages systemd depends on:
ii  acl             2.2.52-2
ii  adduser         3.113+nmu3
ii  initscripts     2.88dsf-53.4
ii  libacl1         2.2.52-2
ii  libaudit1       1:2.4-1
ii  libblkid1       2.20.1-5.11
ii  libc6           2.19-11
ii  libcap2         1:2.24-6
ii  libcap2-bin     1:2.24-6
ii  libcryptsetup4  2:1.6.6-1
ii  libgcrypt20     1.6.2-3
ii  libkmod2        18-3
ii  liblzma5        5.1.1alpha+20120614-2
ii  libpam0g        1.1.8-3.1
ii  libselinux1     2.3-2
ii  libsystemd0     215-5+b1
ii  sysv-rc         2.88dsf-53.4
ii  udev            215-5+b1
ii  util-linux      2.20.1-5.11

Versions of packages systemd recommends:
ii  dbus            1.8.8-1+b1
ii  libpam-systemd  215-5+b1

Versions of packages systemd suggests:
pn  systemd-ui  <none>

-- no debconf information