kernel-packages team mailing list archive

[Rafael David Tinoco <inaddy@xxxxxxxxxx>]

Fixing typo from previous comment:

I developed a small tool based on inotify to help users to check if
their watchdog is being used.

Anyone can find instructions on how to run it here:

https://github.com/inaddy/notifymydog

Small Example:

inaddy@host:~$ wget https://raw.githubusercontent.com/inaddy/notifymydog/master/notifymydog.c
inaddy@host:~/notifymydog$ gcc -Wall -D_DEBUG=0 -D_SYSLOG=1 notifymydog.c -o notifymydog
inaddy@host:~/notifymydog$ sudo ./notifymydog &
inaddy@host:~$ sudo tail -f /var/log/syslog
Mar 16 17:36:26 inaddygueto WATCHMYDOG[15766]: OK: WATCHDOG UPDATED
Mar 16 17:36:40 inaddygueto WATCHMYDOG[15766]: OK: WATCHDOG UPDATED
Mar 16 17:36:44 inaddygueto WATCHMYDOG[15766]: WARNING: WATCHDOG WAS CLOSED
Mar 16 17:36:49 inaddygueto WATCHMYDOG[15766]: WARNING: WATCHDOG WAS OPENED

So if you ever got a kernel panic on a HP Proliant Server DL360 and/or
DL380 with no apparent reason and the stack trace shows NMIs generate,
confirm if none of your userland programs have opened /dev/watchdog on
purpose (not updating it frequent enough) and by accident (causing the
watchdog HW to be triggered and panic'ing the machine after some time).

Workaround:

# echo "blacklist hpwdt" >> /etc/modprobe.d/blacklist-hp.conf
# update-initramfs -k all -u
# update-grub
# reboot

-- 
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https://bugs.launchpad.net/bugs/1432837

Title:
  HP Proliant Servers - Kernel Panic - NMI - DL360 & DL380 - HPWDT
  module loaded

Status in linux package in Ubuntu:
  Fix Committed
Status in linux source package in Precise:
  In Progress
Status in linux source package in Trusty:
  In Progress
Status in linux source package in Utopic:
  In Progress

Bug description:
  It was brought to me several situations where users where facing
  kernel panics when machine was apparently idling (for some HP Proliant
  Servers like DL 360, DL 380).

  ILO:

  "76 CriticalSystem Error03/12/2015 12:4203/12/2015 12:072 An
  Unrecoverable System Error (NMI) has occurred (System error code
  0x0000002B, 0x00000000)"

  Examples:

  PID: 0      TASK: ffffffff81c1a480  CPU: 0   COMMAND: "swapper/0"
   #0 [ffff88085fc05c88] machine_kexec at ffffffff8104eac2
   #1 [ffff88085fc05cd8] crash_kexec at ffffffff810f26a3
   #2 [ffff88085fc05da0] panic at ffffffff8175b3f2
   #3 [ffff88085fc05e20] sched_clock at ffffffff8101c3b9
   #4 [ffff88085fc05e30] nmi_handle at ffffffff810170e8
   #5 [ffff88085fc05e90] io_check_error at ffffffff8101758e
   #6 [ffff88085fc05eb0] default_do_nmi at ffffffff810176a9
   #7 [ffff88085fc05ed8] do_nmi at ffffffff810177d8
   #8 [ffff88085fc05ef0] end_repeat_nmi at ffffffff8176da21
      [exception RIP: native_safe_halt+6]
      RIP: ffffffff81055186  RSP: ffffffff81c03e90  RFLAGS: 00000246
      RAX: 0000000000000010  RBX: 0000000000000010  RCX: 0000000000000246
      RDX: ffffffff81c03e90  RSI: 0000000000000018  RDI: 0000000000000001
      RBP: ffffffff81055186   R8: ffffffff81055186   R9: 0000000000000018
      R10: ffffffff81c03e90  R11: 0000000000000246  R12: ffffffffffffffff
      R13: 0000000000000000  R14: 0000000000000000  R15: 0000000000000000
      ORIG_RAX: 0000000000000000  CS: 0010  SS: 0018
  --- <DOUBLEFAULT exception stack> ---
   #9 [ffffffff81c03e90] native_safe_halt at ffffffff81055186
  #10 [ffffffff81c03e98] default_idle at ffffffff8101d37f
  #11 [ffffffff81c03eb8] arch_cpu_idle at ffffffff8101dcaf
  #12 [ffffffff81c03ec8] cpu_startup_entry at ffffffff810b5325
  #13 [ffffffff81c03f40] rest_init at ffffffff81751a37
  #14 [ffffffff81c03f50] start_kernel at ffffffff81d320b7
  #15 [ffffffff81c03f90] x86_64_start_reservations at ffffffff81d315ee
  #16 [ffffffff81c03fa0] x86_64_start_kernel at ffffffff81d31733

  OR

  PID: 0 TASK: ffffffff81c14440 CPU: 0 COMMAND: "swapper/0"
  #0 [ffff880fffa07c40] machine_kexec at ffffffff8104b391
  #1 [ffff880fffa07cb0] crash_kexec at ffffffff810d5fb8
  #2 [ffff880fffa07d80] panic at ffffffff81730335
  #3 [ffff880fffa07e00] hpwdt_pretimeout at ffffffffa02378b5 [hpwdt]
  #4 [ffff880fffa07e20] nmi_handle at ffffffff8174a76a
  #5 [ffff880fffa07ea0] default_do_nmi at ffffffff8174aacd
  #6 [ffff880fffa07ed0] do_nmi at ffffffff8174abe0
  #7 [ffff880fffa07ef0] end_repeat_nmi at ffffffff81749c81
  [exception RIP: intel_idle+204]
  RIP: ffffffff813f07ec RSP: ffffffff81c01d88 RFLAGS: 00000046
  RAX: 0000000000000010 RBX: 0000000000000010 RCX: 0000000000000046
  RDX: ffffffff81c01d88 RSI: 0000000000000018 RDI: 0000000000000001
  RBP: ffffffff813f07ec R8: ffffffff813f07ec R9: 0000000000000018
  R10: ffffffff81c01d88 R11: 0000000000000046 R12: ffffffffffffffff
  R13: 0000000001c0d000 R14: ffffffff81c01fd8 R15: 0000000000000000
  ORIG_RAX: 0000000000000000 CS: 0010 SS: 0018
  --- <NMI exception stack> ---
  #8 [ffffffff81c01d88] intel_idle at ffffffff813f07ec
  #9 [ffffffff81c01dc0] cpuidle_enter_state at ffffffff815e76cf

  It turned out that after investigating all idling situations and
  diverse kernel dump files - where we had most of the CPUs either
  MWAITing and or "relaxing", we discovered that HPWDT was loaded and
  corosync was opening /dev/watchdog file, triggering the ILO watchdog
  timer and not updating frequently enough as ILO expected.

  As described in /etc/modprobe.d/blacklist-watchdog.conf:

  """
  # Watchdog drivers should not be loaded automatically, but only if a
  # watchdog daemon is installed.
  """

  We should blacklist module "hpwdt" by default for all Ubuntu versions.

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