From Fedora Project Wiki

Rawhide synchronization for the GNU C Library

Make sure you have authenticated and meet the pre-requisites (see notes below).

Synchronization Process

  • Setup/Fetch a clean upstream master repository for glibc. This can be an existing directory also which you switch to master branch and ensure it has been rebased e.g. git pull --rebase cleanly to head.
mkdir -p $HOME/src
cd $HOME/src
git clone git:// glibc-pristine
  • Setup/Fetch a clean Fedora rawhide glibc repository. If this is not your first time syncing, you may need to remove the glibc-patches subdirectory that the previous sync created.
cd $HOME/fedsrc
fedpkg clone glibc
  • Run fedpkg sources to downloads the .tar.xy file needed for creating the glibc-patches repository (next step).
cd $HOME/fedsrc/glibc
fedpkg sources
  • Convert the Fedora rawhide glibc dist-git repository to a glibc-patches repository (git repo with Fedora patches applied as commits).
export GLIBC_MS=$HOME/fedsrc/glibc-maintainer-scripts
cd $HOME/fedsrc/glibc
  • Synchronize from upstream master to Fedora rawhide and review changes.

NOTE: Pick the appropriate set of instructions based on where we are in the release.

No release transitions occurring:

cd $HOME/fedsrc/glibc
$GLIBC_MS/ --import-git $HOME/src/glibc-pristine --verbose
git diff
Confirm that glibcsrcdir, glibcversion, and Release have the correct NEVRA.

Transitioning from stable release -> master:

cd $HOME/fedsrc/glibc
$GLIBC_MS/ --import-git $HOME/src/glibc-pristine --verbose --import-git-branch master
git diff
Manually change the glibcsrcdir, glibcversion, and Release to match the new NEVRA.

If a merge conflict occurs, review the section on Dealing with Merge Conflicts then return to the next step.

  • Manually document note-worthy changes in the %changelog. This step is probably the most complex. You need to look at all the changes since the last sync (the hash is recorded in the %changelog) in the upstream repo and see if there is anything note-worthy to talk about e.g. git diff HASH1^..HASH2. You will use this text in your commit message also.
* Wed Nov 07 2018 Florian Weimer <> - 2.28.9000-14
- Auto-sync with upstream branch master,
  commit 1df872fd74f730bcae3df201a229195445d2e18a:
- libanl: Fix crash if first helper thread creation failed (#1646381)

A useful command to summarize commits is git log like this:

cd $HOME/src/glibc-pristine
git log --oneline e0cb7b6131..0ddb7ea842 | sed 's/^[^ ]* /- /'

The two hashes to use are based on the last sync's git commit and the current sync's git commit. You want the log listing to show all of the new commits that have been included in the current sync. In the above example, we're updating from e0cb7b6131 (the commit of the last sync) to 0ddb7ea842 (the commit of the current sync). Verify the boundary commits make sense.

  • Add new files (still in the Fedora rawhide directory from the last step) and commit
cd $HOME/fedsrc/glibc
fedpkg new-sources glibc-*.tar.xz
git add glibc.spec
git commit

An appropriate commit message would be:

    Auto-sync with upstream branch master
    Upstream commit: 1df872fd74f730bcae3df201a229195445d2e18a
    - libanl: Fix crash if first helper thread creation failed (#1646381)

Following the spec file %changelog example from above.

  • Test a scratch build, and wait for it to complete.
fedpkg srpm
fedpkg scratch-build --srpm ./glibc-XXX.src.rpm
  • Verify scratch build results by downloading logs and looking for any unexpected failures. A list of known failures is kept at the end of this page, and should be updated as needed.
export TOOLS=$HOME/fedsrc/UpstreamToolchainBuildScripts
  • Lastly, push the commit and kick off a Rawhide build if the logs look good.
git push
fedpkg build


  • Kerberos init with Fedora realm.
  • Make sure your ssh agent has your Fedora ssh key for


  • You have a Fedora account with an SSH key, and have setup your SSH key on by logging in.
  • Install fedpkg, python3-pygit2, python3-rpm and git-merge-changelog
  • Configure your ~/.gitconfig to have entries for name, and a merge driver for GNU Changelogs.
	name = My Name

[merge "merge-changelog"]
        name = GNU-style ChangeLog Merge driver
        driver = /usr/bin/git-merge-changelog
	attributesfile = ~/.gitattributes
  • Configure your ~/.gitattributes
ChangeLog       merge=merge-changelog
  • Clone glibc-maintainer-scripts into $GLIBC_MS for the git synchronization scripts.
export GLIBC_MS=$HOME/fedsrc/glibc-maintainer-scripts
mkdir -p $HOME/fedsrc
cd $HOME/fedsrc
git clone
  • Clone UpstreamToolchainBuildScripts from the Fedora Toolchain team for the build log fetching scripts.
export TOOLS=$HOME/fedsrc/UpstreamToolchainBuildScripts
cd $HOME/fedsrc
git clone

Note: if you plan on editing either of the two git repos you just installed, use ssh:// instead of

Differences for Release Syncs

For syncing a glibc release branch into rawhide, you need to use a command line this, and manually reset the Release number the first time:

$GLIBC_MS/ --import-git-branch release/2.31/master --import-git $HOME/src/glibc-2.31 --verbose

For Fedora release branches, the process is basically the same, except you have to use the Bodhi system to push your build to a release.

  • In the above instructions, use the release branch of glibc (typically like release/2.28/master) and the release branch of Fedora (typically like f29)
  • Click the ? icon in the upper right, to search for "glibc"
  • Note previous updates for wordings and severities
  • Select "Create" in the upper right and create a new update
  • Type "glibc" in the packages field. If there's a popup, select the appropriate entry.
  • type "glibc" in the candidate builds field, select the relevent build from the popup.
  • Click in the "Related bugs" field. If your BZ doesn't show up, type in the number.
  • Fill in the Update Notes field and final details.
  • Submit! The system will advertise the update and request karma. When the update has enough karma, it's automatically pushed out.

Dealing with Merge Conflicts

  • Dealing with merge conflicts due to backport+rebase:

Sometimes, a fix is backported from upstream into rawhide, and subsequently a rebase is scheduled. During this rebase, the backport and its corresponding patch need to be dropped.

One way to achieve this is to manually edit the spec file prior to running glibc-patches-to-git so that the merge conflict is avoided in the first place.

Another way is to let the merge conflict occur, then run git rebase --skip in the glibc-patches directory/repository to skip the application of the current patch (i.e. the one backported, which is causing the merge conflict) and continue the rebase (this rebase is an internal detail of how glibc-sync-upstream is implemented and was started by the script before erroring out due to the conflict).

Then we continue the process by executing glibc-git-to-patches in $HOME/fedsrc/glibc, which now skips the patch when creating glibc-patches.

Finally, we run glibc-patches-to-git --branch master, to bring update dist-git with the recently refreshed glibc-patches.

  • Dealing with Fedora patches that no longer apply cleanly due to changes in rawhide:

Another merge conflict scenario is when a Fedora patch does not apply cleanly. You may see a message like this:

CONFLICT (content): Merge conflict in nss/nsswitch.conf error: Failed to merge in the changes.

In this case, the patch is needed for Fedora but an upstream change has caused the patch to be out of sync. You need to fix the patch in the glibc-patches directory. Using nss/nsswitch.conf as an example:

cd $HOME/fedsrc/glibc/glibc-patches
edit nss/nsswitch.conf to fix the merge conflict
git add nss/nsswitch.conf
git rebase --continue

cd $HOME/fedsrc/glibc

If you see that there is a glibc.spec and

mv glibc.spec glibc.spec.old
mv glibc.spec

Now complete the git-to-patches process, regenerating the patch that failed previously:


You should see a message similar to this:

info: regenerating patch 'glibc-fedora-nsswitch.patch' because patch failed

git add glibc-fedora-nsswitch.patch

Known Acceptable Build Failures

For the purposes of "looking for any unexpected failures" (above), this is the current list of build failures that have been deemed "not to stop a sync". After you complete the scratch build and download the logs, compare the test failures in the logs with the results below. For each failure not listed here, analyze it, determine if it's safe to continue syncing, and add that failure below. For each failure listed below that no longer appears in the test results, remove it from below. I.e. most syncs will require minor updates in this section.

All Hosts


Rawhide (1 fail): FAIL: elf/tst-debug1
=====FAIL: elf/tst-debug1.out=====
Didn't expect signal from child: got `Bus error'
=====FAIL: elf/tst-debug1.test-result=====
FAIL: elf/tst-debug1
original exit status 1


Rawhide (1 fail): FAIL: debug/tst-longjmp_chk2
=====FAIL: debug/tst-longjmp_chk2.out=====
not on alternate stack
 in signal handler
 on alternate stack
Didn't expect signal from child: got `Aborted'
=====FAIL: debug/tst-longjmp_chk2.test-result=====
FAIL: debug/tst-longjmp_chk2
original exit status 1

FAIL: misc/tst-sysvshm-linux

The tst-sysvshm-linux failure is related to:


Rawhide (0 fails): No failures.
FAIL: math/test-float128-j0
FAIL: math/test-float64x-j0
FAIL: math/test-ldouble-j0

These relate to this bug:
FAIL: signal/tst-minsigstksz-1
FAIL: signal/tst-minsigstksz-2


Rawhide (0 fails): No failures.

FAIL: misc/tst-sigcontext-get_pc
Sporadic failure:
FAIL: time/tst-cpuclock1


Rawhide (0 fails): No failures.

Sporadic failure:
FAIL: rt/tst-cpuclock2


Rawhide (1 fail): FAIL: nptl/tst-stack4
=====FAIL: nptl/tst-stack4.out=====
=====FAIL: nptl/tst-stack4.test-result=====
FAIL: nptl/tst-stack4
original exit status 127