Richard Henderson <r...@twiddle.net> writes: Patch at http://patchwork.ozlabs.org/patch/229139/ Thanks. I can confirm that this fixes the bug triggered by my test case (and yours). However, the instability of Debian GNU/Linux x86_64 has not improved.
The exact same Debian version (debian "testing") updated at the same time runs well on hardware. My qemu Debian system now got messed up, since I attempted an upgrade in the buggy qemu, which segfaulted several times during the upgrade. I need to reinstall, and then rely on -snapshot. There is a problem with denorms which is reproducible, but whether that is a qemu bug, and whether it can actually cause the observed instability, is questionable. Here is a testcase for that problem:
qemu-denorm-problem.s
Description: Binary data
It should terminate. The observed buggy behaviour is that it hangs. The instability problem can be observed at gmplib.org/devel/tm-date.html. hwl-deb.gmplib.org is Debian under qemu with -cpu Haswell,+adx. Not that the exact same qemu runs FreeBSD flawlessly (hwl.gmplib.org). It is neither instable nor does it run the denorms testcase poorly. I fully realise this is a hopeless bug report, but I am sure you can reproduce it, since it is far from GMP specific. After all apt-get update; apt-get upgrade triggered it. Debugging it will be a nightmare. Qemu version: main git repo from less than a week ago + Richard ADX patch. -- Torbjörn
