LTSP boot fails, missing -stable patch "net: avoid dependency of net_get_random_once on nop patching"

[Jakob Unterwurzacher]

The patch

    net: switch net_secret key generation to net_get_random_once
    https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=e34c9a69970d8664a36b46e6445a7cc879111cfd

introduced a regression into kernel 3.13 that makes the kernel's nbd client always use the same source port number (on some hardware). This means that the second and subsequent boots for an LTSP client fail because the sourceip / sourceport pair on the nbd server is still occupied by the old nbd connection.

The patch

    net: avoid dependency of net_get_random_once on nop patching
    https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=3d4405226d27b3a215e4d03cfa51f536244e5de7

should fix the issue and also went into -stable:

http://www.spinics.net/lists/netdev/msg282397.html
https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/?id=adeb3fe4ef6621793d7f1d6f0b9c9cc88827c5b7 )

There are three independent reports on ltsp-discuss for this issue and the original analysis was posted here: https://<email address hidden>/msg41764.html
The issue can NOT be reproduced in VirtualBox and may be limited to certain hardware - other users report they see no problems with 3.13. However, as this is a -stable patch it should be applied anyway.

[Luis Henriques (henrix)]

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-trusty' to 'verification-done-trusty'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Jakob Unterwurzacher (jakobunt)]

I tested kernel version 3.13.0-32-generic (uname -a), 3.13.0.32.38 (package version) - it fixes the issue.

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 3.13.0-32.57

---------------
linux (3.13.0-32.57) trusty; urgency=low

  [ Upstream Kernel Changes ]

  * l2tp: Privilege escalation in ppp over l2tp sockets
    - LP: #1341472
    - CVE-2014-4943

linux (3.13.0-32.56) trusty; urgency=low

  [ Luis Henriques ]

  * Merged back Ubuntu-3.13.0-30.55 security release
  * Revert "x86_64,ptrace: Enforce RIP <= TASK_SIZE_MAX (CVE-2014-4699)"
    - LP: #1337339
  * Release Tracking Bug
    - LP: #1338524

  [ Upstream Kernel Changes ]

  * ptrace,x86: force IRET path after a ptrace_stop()
    - LP: #1337339
    - CVE-2014-4699
  * hpsa: add new Smart Array PCI IDs (May 2014)
    - LP: #1337516

linux (3.13.0-31.55) trusty; urgency=low

  [ Luis Henriques ]

  * Release Tracking Bug
    - LP: #1336278

  [ Andy Whitcroft ]

  * [Config] switch hyper-keyboard to virtual
    - LP: #1325306
  * [Packaging] linux-udeb-flavour -- standardise on linux prefix

  [ dann frazier ]

  * [Config] CONFIG_GPIO_DWAPB=m
    - LP: #1334823

  [ Feng Kan ]

  * SAUCE: (no-up) arm64: dts: Add Designware GPIO dts binding to APM
    X-Gene platform
    - LP: #1334823

  [ John Johansen ]

  * SAUCE: (no-up) apparmor: fix apparmor spams log with warning message
    - LP: #1308761

  [ Kamal Mostafa ]

  * [Config] updateconfigs ACPI_PROCFS_POWER=y after v3.13.11.4 rebase

  [ Loc Ho ]

  * SAUCE: (no-up) phy-xgene: Use correct tuning for Mustang
    - LP: #1335636

  [ Michael Ellerman ]

  * SAUCE: (no-up) powerpc/perf: Ensure all EBB register state is cleared
    on fork()
    - LP: #1328914

  [ Ming Lei ]

  * Revert "SAUCE: (no-up) rtc: Add X-Gene SoC Real Time Clock Driver"
    - LP: #1274305

  [ Suman Tripathi ]

  * SAUCE: (no-up) libahci: Implement the function ahci_restart_engine to
    restart the port dma engine.
    - LP: #1335645
  * SAUCE: (no-up) ata: Fix the dma state machine lockup for the IDENTIFY
    DEVICE PIO mode command.
    - LP: #1335645

  [ Tim Gardner ]

  * [Config] CONFIG_POWERNV_CPUFREQ=y for powerpc, ppc64el
    - LP: #1324571
  * [Debian] Add UTS_UBUNTU_RELEASE_ABI to utsrelease.h
    - LP: #1327619
  * [Config] CONFIG_HAVE_MEMORYLESS_NODES=y
    - LP: #1332063
  * [Config] CONFIG_HID_RMI=m
    - LP: #1305522

  [ Upstream Kernel Changes ]

  * Revert "offb: Add palette hack for little endian"
    - LP: #1333430
  * Revert "net: mvneta: fix usage as a module on RGMII configurations"
    - LP: #1333837
  * Revert "USB: serial: add usbid for dell wwan card to sierra.c"
    - LP: #1333837
  * Revert "macvlan : fix checksums error when we are in bridge mode"
    - LP: #1333838
  * serial: uart: add hw flow control support configuration
    - LP: #1328295
  * mm/numa: Remove BUG_ON() in __handle_mm_fault()
    - LP: #1323165
  * Tools: hv: Handle the case when the target file exists correctly
    - LP: #1306215
  * Documentation/devicetree/bindings: add documentation for the APM X-Gene
    SoC RTC DTS binding
    - LP: #1274305
  * drivers/rtc: add APM X-Gene SoC RTC driver
    - LP: #1274305
  * arm64: add APM X-Gene SoC RTC DTS entry
    - LP: #1274305
  * powerpc/perf: Add Power8 cache & TLB events
    - LP: #1328914
  * powerpc/perf: Configure BH...

[Vagrant Cascadian (vagrantc)]

Using linux-image-3.13.0-32-generic 3.13.0-32.57, I'm still seeing something with similar, if not identical, symptoms...

[Vagrant Cascadian (vagrantc)]

correction, i had a misconfiguration in my nbd-server that merely had similar symptoms... 3.13.0-3257 works fine.