I’ve written a test case that clearly demonstrates the GCC 4.8 bug responsible for the kadmin.local failure:
$ gcc-4.8 -Wall -O2 bug.c -o bug $ ./bug $ echo $? 1 $ gcc-4.9 -Wall -O2 bug.c -o bug $ ./bug $ echo $? 0 A git bisection of the GCC source shows that this bug disappeared in https://gcc.gnu.org/r202525. However, I don’t understand why; the fact that r202525 was intended to fix a “missed-optimization” bug (https://gcc.gnu.org/PR58404) is a little bit terrifying. ** Also affects: gcc-4.8 (Ubuntu) Importance: Undecided Status: New ** Attachment added: "Reduced test case for GCC 4.8 bug" https://bugs.launchpad.net/ubuntu/+source/krb5/+bug/1347147/+attachment/4165776/+files/bug.c -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to gcc-4.8 in Ubuntu. https://bugs.launchpad.net/bugs/1347147 Title: krb5 database propagation enters infinite loop Status in “gcc-4.8” package in Ubuntu: New Status in “krb5” package in Ubuntu: Confirmed Bug description: In some conditions, propagating a kerberos database to a slave KDC server can stall. This is due to a misoptimization by gcc 4.8 of the CIRCLEQ famliy of macros, apparently due to overzealous strict aliasing deductions. One case of this stall is reported at http://mailman.mit.edu/pipermail/kerberos/2014-July/020007.html (and the rest of the thread), and there is an entry in the upstream bugtracker at http://krbdev.mit.edu/rt/Ticket/Display.html?id=7860 . gcc 4.9 (as used in Debian unstable at present) is not believed to induce this problem. Upstream has patched their code to use the TAILQ family of macros instead, as a workaround, but that workaround has not yet appeared in an upstream release: https://github.com/krb5/krb5/commit/26d8744129 Because of the different compiler versions used on Debian and Ubuntu, I am filing this as an Ubuntu-specific bug. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gcc-4.8/+bug/1347147/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
