kernel-packages team mailing list archive

[Janne Snabb <1450442@xxxxxxxxxxxxxxxxxx>]

I encountered this issue on a Hetzner VPS. It is a KVM based virtual
server, not VMware. After rebooting I was unable to login through ssh.
Accessing the system from console was possible thugh running many
commands resulted in "Killed". The kernel stack trace was the same as in
the original bug report.

There is no quick and dirty workaround documented yet on this bug
report, so I add it.

Do the following to get your system quickly back to usable state while
waiting for the patched kernel:

1) disable starting "auditd" at boot (for example "chmod 000
/etc/init.d/auditd" is an easy and ugly way to do it)

2) reboot the system (in my case the "reboot" command did not work, I
had to hard-reset the system)

Done.

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https://bugs.launchpad.net/bugs/1450442

Title:
  Kernel Oops - unable to handle kernel NULL pointer dereference at
  (null);  Call Trace: [<ffffffff810fb39b>] ?
  audit_compare_dname_path+0x2b/0xa0

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

Bug description:
  [Impact]
  Ubuntu VMWare instances running 3.13.0-51 will crash with the following backtrace:

  [   12.357276] BUG: unable to handle kernel NULL pointer dereference at           (null)
  [   12.357886] IP: [<ffffffff8136cb80>] strlen+0x0/0x30
  [   12.358457] PGD 230fe9067 PUD 230d5c067 PMD 0
  [   12.359034] Oops: 0000 [#1] SMP
  [   12.359590] Modules linked in: tcp_diag inet_diag vmw_vsock_vmci_transport vsock ip6t_REJECT xt_hl ip6t_rt nf_conntrack_ipv6 nf_defrag_ipv6 ipt_REJECT xt_LOG xt_limit xt_tcpudp xt_addrtype nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack ip6table_filter ip6_tables nf_conntrack_netbios_ns nf_conntrack_broadcast nf_nat_ftp nf_nat nf_conntrack_ftp nf_conntrack crct10dif_pclmul iptable_filter crc32_pclmul ip_tables ghash_clmulni_intel aesni_intel aes_x86_64 ppdev lrw x_tables gf128mul vmwgfx glue_helper ablk_helper cryptd ttm drm vmw_balloon serio_raw shpchp parport_pc lp i2c_piix4 parport mac_hid vmw_vmci psmouse mptspi vmw_pvscsi e1000 mptscsih floppy vmxnet3 mptbase
  [   12.364773] CPU: 2 PID: 1718 Comm: fail2ban-server Not tainted 3.13.0-51-generic #84-Ubuntu
  [   12.365587] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/14/2014
  [   12.367276] task: ffff880230fc3000 ti: ffff8802308c4000 task.ti: ffff8802308c4000
  [   12.368159] RIP: 0010:[<ffffffff8136cb80>]  [<ffffffff8136cb80>] strlen+0x0/0x30
  [   12.369073] RSP: 0018:ffff8802308c5d60  EFLAGS: 00010212
  [   12.369963] RAX: 000000000000000d RBX: 000000000000000d RCX: 0000000000002df0
  [   12.370973] RDX: 0000000000000012 RSI: 0000000000000000 RDI: 0000000000000000
  [   12.372005] RBP: ffff8802308c5d90 R08: ffff8800b9218648 R09: ffff8802308c5d60
  [   12.372988] R10: 0000000000000002 R11: ffff88023082e180 R12: 0000000000000012
  [   12.373901] R13: 0000000000000000 R14: ffff880231f1b3f8 R15: ffff8800b9218460
  [   12.374827] FS:  00007f196f84c740(0000) GS:ffff88023fd00000(0000) knlGS:0000000000000000
  [   12.375752] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [   12.376667] CR2: 0000000000000000 CR3: 0000000230872000 CR4: 00000000000407e0
  [   12.377684] Stack:
  [   12.378612]  ffffffff810fb39b 0000000000000000 0000000000000004 ffff88022ff74838
  [   12.379559]  ffff8800b9218400 ffff8800b9218460 ffff8802308c5df8 ffffffff810fdb36
  [   12.380516]  ffffffff811d56e0 000000042ff74838 ffff880231f1b3c0 ffff88022febecf8
  [   12.381506] Call Trace:
  [   12.382630]  [<ffffffff810fb39b>] ? audit_compare_dname_path+0x2b/0xa0
  [   12.383784]  [<ffffffff810fdb36>] __audit_inode_child+0xb6/0x330
  [   12.384912]  [<ffffffff811d56e0>] ? d_instantiate+0x50/0x70
  [   12.386013]  [<ffffffff811ca060>] vfs_mknod+0x110/0x160
  [   12.387145]  [<ffffffff816bf475>] unix_bind+0x2a5/0x360
  [   12.388207]  [<ffffffff810ff142>] ? __audit_sockaddr+0x42/0x80
  [   12.389250]  [<ffffffff8160d4c0>] SYSC_bind+0xe0/0x120
  [   12.390297]  [<ffffffff8172e9fa>] ? do_page_fault+0x1a/0x70
  [   12.391303]  [<ffffffff8160e4de>] SyS_bind+0xe/0x10
  [   12.392426]  [<ffffffff817330bd>] system_call_fastpath+0x1a/0x1f
  [   12.393581] Code: 89 f8 48 89 e5 f6 82 40 c7 84 81 20 74 15 0f 1f 44 00 00 48 83 c0 01 0f b6 10 f6 82 40 c7 84 81 20 75 f0 5d c3 66 0f 1f 44 00 00 <80> 3f 00 55 48 89 e5 74 15 48 89 f8 0f 1f 40 00 48 83 c0 01 80
  [   12.396831] RIP  [<ffffffff8136cb80>] strlen+0x0/0x30
  [   12.397812]  RSP <ffff8802308c5d60>
  [   12.398769] CR2: 0000000000000000
  [   12.399743] ---[ end trace 2c5a33d31a03347e ]---

  We've also seen this on our precise machines that are running the
  backported trusty kernel.

  When reverting to kernel 3.13.0-49 this no longer occurs.

  [Test Case]
  1) Run an Ubuntu VMWare instance with the affected kernel.

  apt-get install auditd
  echo "-w /etc/test" >>/etc/audit/audit.rules
  /etc/init.d/auditd restart
  apt-get install linux-headers-3.13.0-51 linux-headers-3.13.0-51-generic linux-image-3.13.0-51-generic
  reboot
  attempt to login or ssh into the host - you'll get a similar stacktrace.

  
  [Fix]
  commit fcf22d8267ad2601fe9b6c549d1be96401c23e0b upstream

  --

  uname -a:
  Linux search-2 3.13.0-51-generic #84-Ubuntu SMP Wed Apr 15 12:08:34 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

  cat /proc/version_signature:
  Ubuntu 3.13.0-51.84-generic 3.13.11-ckt18

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