[Bug 1237042] Re: ureadahead source needs "tracing_enabled" changed to "tracing_on" for 12.04.3

[Lucas Magasweran]

The following error could also indicate that your kernel doesn't have
the required tracepoints.

ureadahead: Error while tracing: No such file or directory

If you're not running a stock Ubuntu kernel you will need a patch [1]
(worked on my 4.14 Debian kernel). Unfortunately, these trace events
will not be upstreamed [2].

[1] http://kernel.ubuntu.com/git/ubuntu/ubuntu-
xenial.git/commit/?h=hwe&id=7744c33fdad887074a481fd4d21ccb6670ac62e6

[2] https://patchwork.kernel.org/patch/9254717/

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https://bugs.launchpad.net/bugs/1237042

Title:
  ureadahead source needs "tracing_enabled" changed to "tracing_on" for
  12.04.3

Status in ureadahead package in Ubuntu:
  Confirmed

Bug description:
  On a fresh install of Ubuntu 12.04.3 (64-bit), ureadahead was always
  exiting with status code 5.

  When manually run as:  sudo /sbin/ureadahead --force-trace --debug
  The output is:
  Counted 4 CPUs
  trace: Missing uselib tracing: No such file or directory
  ureadahead: Error while tracing: No such file or directory

  The uselib tracing notice is not important.  The "error while tracing" notice lead me to compare ureadahead sources between 12.04.3 and 13.04.  Note that ureadahead in 13.04 works.  I noticed this difference on lines 195 and 232:
  	if (set_value (dfd, "tracing_enabled",
  vs:
  	if (set_value (dfd, "tracing_on",

  This change is mentioned in the changelog as:

  ureadahead (0.100.0-13) raring; urgency=low
    * src/trace.c: tracing_enabled is deprecated and gone, switch to tracing_on
      (LP: #1085766).
   -- Andy Whitcroft <apw at ubuntu.com>  Fri, 11 Jan 2013 12:05:17 +0000

  I suspect that this issue occurs in 12.04.3 because it is now using
  the newer raring kernel 3.8.0-31.  Previous flavors of 12.04 such as
  12.04.2 do not seem to exhibit this ureadahead issue, probably because
  the kernel is older 3.5.xx.

  As a proof-of-concept test, I hex edited the 12.04.3 /sbin/ureadahead
  to change "tracing_enabled" to "tracing_on".  Upon reboot, now
  ureadahead works, generates the /var/lib/ureadahead/pack file, and it
  does not report status code 5.

  Another workaround is to use the ureadahead binary from 13.04, but the
  updated /lib/x86_64-linux-gnu/libext2fs.so.2.4 is also required from
  13.04.

  
  $ lsb_release -rd
  Description:	Ubuntu 12.04.3 LTS
  Release:	12.04

  $ apt-cache policy ureadahead
  ureadahead:
    Installed: 0.100.0-12
    Candidate: 0.100.0-12
    Version table:
   *** 0.100.0-12 0
          500 http://mirror.peer1.net/ubuntu/ precise/main amd64 Packages
          100 /var/lib/dpkg/status

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