On Mon, Feb 24, 2025 at 1:21 PM Florian Weimer <f...@deneb.enyo.de> wrote:
> * Attila Szegedi: > > >> That seems … quite unlikely. GCC 8 has seen extensive use on > >> AArch64, on a variety of implementations, and I don't recall > >> problems in this area. I don't follow AArch64 *that* closely, > >> admittedly, but I expect it would have caused quite a ruckus. > >> > > > > Yeah. The lack of discussion also led me to believe that even if this is > an > > issue, it's definitely not a widely encountered one. (It's also possible > > that it's a red herring, although, well, as I said, forcing general regs > > only did fix it.) > > Is it non-deterministic? It might be a context switching issue in the > kernel/hypervisor/firmware. I usually don't notice fixes for those > because they do not lead to questions whether it's necessary to > rebuild the whole distribution. These bugs do happen from time to time: > > [PATCH v3 0/8] KVM: arm64: FPSIMD/SVE/SME fixes > < > https://lore.kernel.org/linux-arm-kernel/20250210195226.1215254-1-mark.rutl...@arm.com/ > > > Huh. That is interesting. Yes, it is non-deterministic. And it does occur solely in containerized environments, so it's eminently possible it's a hypervisor issue. (Still, a bit amusing that nothing came up with regard to how I don't see GCC 12 schedule pointers onto aarch64 FP registers anymore :-). I understood from Kyrylo's post that it's probably because no such explicit decision was made.) Attila.
