[Bug 1868272] Re: FFe: bind9 9.16.1 update

[Andreas Hasenack]

** Description changed:

  Bind just released 9.16.1. Focal has 9.16.0. This release was expected
  and is considered important, as it's the first point release after a new
  major one, and we should have it in focal.
  
  Release notes: https://downloads.isc.org/isc/bind9/9.16.1/RELEASE-NOTES-
  bind-9.16.1.html
  
  More detailed notes: https://gitlab.isc.org/isc-
  projects/bind9/-/blob/v9_16/CHANGES (look in the 9.16.1 section)
  
  The one change that is indeed a feature change, and not a bug fix, is mentioned in the release notes only:
  """
  Feature Changes
  
      The system-provided POSIX Threads read-write lock implementation is now used by default instead of the native BIND 9 implementation. Please be aware that glibc versions 2.26 through 2.29 had a bug that could cause BIND 9 to deadlock. A fix was released in glibc 2.30, and most current Linux distributions have patched or updated glibc, with the notable exception of Ubuntu 18.04 (Bionic) which is a work in progress. If you are running on an affected operating system, compile BIND 9 with --disable-pthread-rwlock until a fixed version of glibc is available. [GL !3125]
  """
  
  The linked upstream glibc bug[1] still affects[2] bionic, and bionic
  only. I prepared an SRU for it, but I'm out of my depth on that one. I
  basically grabbed the patch, test case, and confirmed the test case no
  longer locks up with the patch applied.
  
  Focal doesn't have that bug, but it's still worth to call out this
  change. It's upstream's new default, so they must have good reasoning
  for it. I emailed[3] the bind-users@ mailing list asking if they have
  more details on what that change means, or why it was made.
  
- We can always disable it, by passing --disable-pthread-rwlock.
+ We can always disable it, by passing --disable-pthread-rwlock, in which
+ case this FFe won't be strictly necessary.
  
  PPA with test packages (where I did *NOT* pass --disable-pthread-rwlock,
  i.e., it's using upstream's default): https://launchpad.net/~ci-train-
  ppa-service/+archive/ubuntu/3984/
  
  Bileto ticket with green tests (bar i386, known):
  https://bileto.ubuntu.com/#/ticket/3984
  
  1. https://sourceware.org/bugzilla/show_bug.cgi?id=23844#c14
  2. https://bugs.launchpad.net/ubuntu/+source/glibc/+bug/1864864
  3. https://lists.isc.org/pipermail/bind-users/2020-March/102786.html

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https://bugs.launchpad.net/bugs/1868272

Title:
  FFe: bind9 9.16.1 update

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