On Thu, 2010-04-15 at 09:32 +0200, Ingo Molnar wrote: > It trades robustness for slightly better space/code efficiency. > > Such a trap based mechanism exists on x86 as well and we use it for BUG_ON(). > We intentionally dont use it to generate warnings and dont override __WARN(), > because it would blow up way too often when a warning triggers in some > sensitive codepath that cannot take a trap. > > Anyway, the warning obviously has to be fixed - but the boot crash itself is > PowerPC's own doing. Well, yes and no, as I explained in a separate branch of that thread. We indeed can't cope with a WARN in that spot because it goes recursive. Now the reason we have this double-enable is due afaik to the way I implemented IRQ trace, because things like syscalls basically force-enable IRQs on powerpc and I don't necessarily have tracking informations in the exception return path of what the "old" value was. I need to double check what the exact scenario here is and whether I can fix it but it's one of those cases where what lockdep is warning about isn't actually an error I believe. Cheers, Ben. -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
