[regression] tar testsuite failure seen when built with gcc-4.8 Linaro

[Matthias Klose]

On arm-linux-gnueabihf GNU tar 1.27 fails the test

  114: time: tricky time stamps FAILED (time01.at:23)

when built with gcc-4.8 Linaro, checked with both the 09 and 10 releases.
works with FSF GCC 4.8.2,
works with gcc-4.7 Linaro.
works with GCC 4.8 Linaro without optimization (-O0, fails with both -O1 and -O2)

[Matthias Klose (doko)]

fails with fsf trunk 20131021 too

[Christophe Lyon (christophe-lyon)]

Do you know if it fails on armhf only or on other targets? (arm, x86)

[Matthias Klose (doko)]

works on i686, x86_64, powerpc and aarch64.

[Christophe Lyon (christophe-lyon)]

OK with gcc-linaro-4.8-2013.04
FAILS with gcc-linaro-4.8-2013.05

[Christophe Lyon (christophe-lyon)]

Checking intermediate revisions between 2013.04 and 2013.05 indicate that the regression was introduced by commit 122016, which is the backport of trunk r197518-197522,197526-197528 (which means 8 patches).

[Christophe Lyon (christophe-lyon)]

Reverting commit 197526 makes the test pass.
Now investigating the code generation differences to see if that patch can be fixed or if it should be reverted.

[Christophe Lyon (christophe-lyon)]

Committed revert of 197526 as 204671, so that the tests pass with our next release.
More time needed to actually fix the original patch, and to look more carefully at tar's code.

[Matthias Klose (doko)]

fixed in trusty

[Adam Conrad (adconrad)]

Hello Matthias, or anyone else affected,

Accepted gcc-4.8 into saucy-proposed. The package will build now and be available at http://launchpad.net/ubuntu/+source/gcc-4.8/4.8.1-10ubuntu9 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, and change the tag from verification-needed to verification-done. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Matthias Klose (doko)]

the tar-1.17 testsuite now passes on armhf in saucy-proposed.

[Brian Murray (brian-murray)]

The verification of the Stable Release Update for gcc-4.8 has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regresssions.

[Launchpad Janitor (janitor)]

This bug was fixed in the package gcc-4.8 - 4.8.1-10ubuntu9

---------------
gcc-4.8 (4.8.1-10ubuntu9) saucy-proposed; urgency=low

  * Fix miscompilation of tar on armhf. LP: #1243656.
  * Fix PR libstdc++/58800, taken from the 4.8 branch. LP: #1246802.
 -- Matthias Klose <email address hidden> Fri, 15 Nov 2013 12:20:27 +0100