[Bug 1908307] Autopkgtest regression report (glibc/2.31-0ubuntu9.2)

[Ubuntu SRU Bot]

All autopkgtests for the newly accepted glibc (2.31-0ubuntu9.2) for focal have finished running.
The following regressions have been reported in tests triggered by the package:

python-llfuse/1.3.6+dfsg-2build1 (ppc64el)
mercurial/5.3.1-1ubuntu1 (amd64)
datefudge/1.23ubuntu1 (ppc64el)
yade/2020.01a-6build2 (s390x)
raspell/1.3-2build1 (s390x)
burp/2.2.18-2 (arm64)
gnudatalanguage/0.9.9-12build1 (amd64)
threadweaver/5.68.0-0ubuntu1 (amd64)
rancid/3.11-1 (s390x)
r-other-x4r/1.0.1+git20150806.c6bd9bd-2build1 (s390x)
libxmlb/0.1.15-2 (amd64)
feersum/1.407-2 (s390x)
libimage-sane-perl/5-1 (arm64)
gnome-photos/3.34.1-1 (ppc64el)
mbedtls/2.16.4-1ubuntu2 (amd64)
libreoffice/1:6.4.6-0ubuntu0.20.04.1 (armhf)
reprotest/0.7.14 (s390x, arm64)
puma/3.12.4-1ubuntu2 (arm64, s390x)
libdbd-mariadb-perl/1.11-3ubuntu2 (armhf, arm64, amd64, s390x, ppc64el)
python3-lxc/1:3.0.4-1ubuntu6 (s390x)
mpi4py/3.0.3-4build2 (amd64)
nut/2.7.4-11ubuntu4 (s390x)
r-cran-processx/3.4.2-1 (amd64)
boost1.71/1.71.0-6ubuntu6 (amd64)
netplan.io/0.100-0ubuntu4~20.04.3 (amd64)
php-luasandbox/3.0.3-2build2 (armhf)
libtext-markdown-discount-perl/0.12-1 (armhf)
mysql-connector-c++/1.1.12-4ubuntu2 (s390x)
xmobar/0.29.4-2build3 (ppc64el)
golang-github-xenolf-lego/3.2.0-1 (armhf, arm64, amd64, s390x, ppc64el)
cffi/1:0.21.0-1 (amd64)
websocketd/0.3.1-3 (armhf)
cmark-gfm/0.29.0.gfm.0-4 (amd64)
ruby2.7/2.7.0-5ubuntu1.2 (arm64)
golang-github-bmatsuo-lmdb-go/1.8.0+git20170215.a14b5a3-2 (amd64)
lazarus/2.0.6+dfsg-3 (armhf)
gnutls28/3.6.13-2ubuntu1.3 (i386, s390x, ppc64el, armhf, arm64, amd64)
dogtag-pki/10.8.3-1ubuntu1 (armhf, arm64, amd64, s390x, ppc64el)
booth/1.0-174-gce9f821-1 (arm64)
apache2/2.4.41-4ubuntu3.1 (armhf)
libpff/20180714-2 (armhf, arm64, amd64, s390x, ppc64el)


Please visit the excuses page listed below and investigate the failures, proceeding afterwards as per the StableReleaseUpdates policy regarding autopkgtest regressions [1].

https://people.canonical.com/~ubuntu-archive/proposed-
migration/focal/update_excuses.html#glibc

[1] https://wiki.ubuntu.com/StableReleaseUpdates#Autopkgtest_Regressions

Thank you!

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https://bugs.launchpad.net/bugs/1908307

Title:
  Please ship a glibc build for profiling in libc6-prof

Status in glibc package in Ubuntu:
  Fix Committed
Status in glibc source package in Focal:
  Fix Committed
Status in glibc source package in Groovy:
  Fix Committed

Bug description:
  [Impact]

  * The C library shipped in libc6 is built with GCC's default behavior
  of omitting the frame pointer that makes tracing and profiling harder.
  Building GLibc with -fno-omit-frame-pointer and shipping it in an
  optional libc6-prof binary package would help tracing and profiling
  efforts.

  [Test Case]

  * Install libc6-prof and start tracing in one shell:

    sudo bpftrace -e 't:syscalls:sys_enter_clock_nanosleep /comm == "sleep"/ {printf("%s\n", ustack);}'
    Attaching 1 probe...

          clock_nanosleep+94
          __nanosleep+23
          0x5652a2e6b827

  * Run the traced program in a different shell
   env LD_LIBRARY_PATH=/lib/libc6-prof/x86_64-linux-gnu sleep 1

  
  * Repeat it without using the libc6-prof library:


   ubuntu at ff-glibc:~$ sleep 1

   ubuntu at ff-glibc:~$ sudo bpftrace -e 't:syscalls:sys_enter_clock_nanosleep /comm == "sleep"/ {printf("%s\n", ustack); }'
   Attaching 1 probe...

          clock_nanosleep+84

  [ Where problems could occur ]

  * Glibc does not build for some architectures with the additional -fno-omit-frame-pointer option which is tracked in LP: #1898049.
  * The -fno-omit-frame-pointer option may sneak in to the regular build, this is convered in the test case.
  * Libc6-prof may be slower thanks to the -fno-omit-frame-pointer option, this is expected and this is the reason for shipping it in a separate package.

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