On Sun, Jun 29, 2014 at 08:06:36PM +0100, Nick Warne wrote: > OK, I just spent three months building GCC 4.7.4 today (thank god the > world cup is on to watch instead)
Yep, the world cup helps a lot with tedious debugging work. :-) > and 3.15.2 built fine, and server is up and > running great. > > This then is an old(er) version of GCC issue (but I dunno what). Right, so the error points at __spin_lock_mb_cache_entry(struct mb_cache_entry *ce) { spin_lock(bgl_lock_ptr(mb_cache_bg_lock, <--- (hash_64((unsigned long)ce, __builtin_log2(8))))); } somewhere here and I'd guess that old gcc is issuing some lib function which uses SSE. And after we disabled all FPU stuff in the kernel with b399fe355b30 ("x86: Disable generation of traditional x87 instructions") that would issue such an error. And I was about to point at that __builtin_log2 thing which looked suspicious and found this by chance: http://lkml.kernel.org/r/1401471304-37479-1-git-send-email-t...@hp.com You could test this patch with that old gcc 4.2.x as it looks like a good candidate for a fix for your issue. :-) -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/