On Mon, Jan 17, 2022 at 12:32:36PM +0100, Jakub Jelinek wrote: > On Sun, Jan 16, 2022 at 05:58:10PM +0000, Richard W.M. Jones wrote: > > I tried recompiling qemu and it fails with an odd error in the RCU > > torture test. Bug submitted upstream here: > > > > https://gitlab.com/qemu-project/qemu/-/issues/823 > > > > ... but since GCC 12 is the only big thing that has changed since we > > just rebuilt qemu, could that be a reason? > > > > https://gitlab.com/qemu-project/qemu/-/blob/1cd2ad11d37c48f284f557954e1df675b126264c/tests/unit/rcutorture.c#L320 > > > > Anyway I'll try to nudge someone on the virt team who knows about > > these things to take a look. > > Does -O0 help? -flto vs. -fno-lto? -fno-ipa-modref (gcc 12 is slightly > more aggressive in the interprocedural TBAA)? > If -O0 helps, can you find out if it is the test or something in a library or > whatever that the test uses, and if the latter, try to bisect it to one *.o > file? If -O0 doesn't help, try to mix and match gcc 11 and gcc 12 built > objects. I know next to nothing about qemu, so it would help if somebody > familiar with it did that. Perhaps Paolo Bonzini is familiar with both > qemu and gcc... > Having just one preprocessed source + compiler command line and knowing > roughly what to look for allows bisection and further analysis. Partially answered here: https://gitlab.com/qemu-project/qemu/-/issues/823 Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com libguestfs lets you edit virtual machines. Supports shell scripting, bindings from many languages. http://libguestfs.org _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx Do not reply to spam on the list, report it: https://pagure.io/fedora-infrastructure
