[Bug 1878723] Re: Kernel panic when used with upstart after 0.11-4ubuntu2.1 update

[Dan Streetman]

> Attempts to install libjson-c2_0.11-4ubuntu2.2_amd64.deb result in the
same lockup which can only be recovered with a hard reboot.

The 2.2 version includes only a revert of the patch, so for any system
affected by this, the currently-running init still contains the faulty
code, and the fixed package's post-install script calls telinit on the
currently-running init, which triggers the problem.  Work is in progress
to produce a new version that also adjusts the package's post-install
script to detect the problematic version and avoid calling telinit.


For impacted systems, you can follow this process to upgrade to the 0.11-4ubuntu2.2_amd64.deb package version:

- Obtain the latest package:
```
$ curl -LO https://launchpad.net/ubuntu/+archive/primary/+files/libjson-c2_0.11-4ubuntu2.2_amd64.deb
```

- Unpack (install without configuring) the package:
```
$ dpkg --unpack libjson-c2_0.11-4ubuntu2.2_amd64.deb
```

- Reboot; this is mandatory in order to proceed:
```
$ sudo reboot
```

- Configure the package:
```
$ sudo apt install -f
```

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https://bugs.launchpad.net/bugs/1878723

Title:
  Kernel panic when used with upstart after 0.11-4ubuntu2.1 update

Status in json-c package in Ubuntu:
  Triaged

Bug description:
  Installing the 0.11-4ubuntu2.1 security update on a Xenial system with
  upstart installed, the system crashes with a kernel panic.

  The error message is:

  [   99.992278] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000100
  [   99.992278] 
  [   99.996057] CPU: 0 PID: 1 Comm: init Not tainted 4.4.0-1105-aws #116-Ubuntu
  [   99.996057] Hardware name: Xen HVM domU, BIOS 4.2.amazon 08/24/2006
  [   99.996057]  0000000000000086 0f10ff6977efbf32 ffff88003d45fe10 ffffffff8140926b
  [   99.996057]  ffffffff81caddf8 ffff88003d45fea8 ffff88003d45fe98 ffffffff81195a84
  [   99.996057]  ffff880000000010 ffff88003d45fea8 ffff88003d45fe40 0f10ff6977efbf32
  [   99.996057] Call Trace:
  [   99.996057]  [<ffffffff8140926b>] dump_stack+0x6d/0x92
  [   99.996057]  [<ffffffff81195a84>] panic+0xd3/0x227
  [   99.996057]  [<ffffffff81088ded>] do_exit+0xb9d/0xba0
  [   99.996057]  [<ffffffff81088e77>] do_group_exit+0x47/0xb0
  [   99.996057]  [<ffffffff81088ef4>] SyS_exit_group+0x14/0x20
  [   99.996057]  [<ffffffff818449db>] entry_SYSCALL_64_fastpath+0x22/0xcb
  [   99.996057] Kernel Offset: disabled

  Downgrading to libjson-c2_0.11-4ubuntu2 resolves the issue.

  Steps to reproduce:
  * Create a system with Xenial installed (I'm using an AWS instance with AMI ami-0f2ed58082cb08a4d)
  * Install upstart: apt-get install upstart-sysv
  * Reboot
  * Update apt and upgrade the packages: apt-get update && apt-get upgrade . This causes the kernel panic.
  * To repeat the kernel panic, run dpkg --configure -a

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