On Thu, Jul 24, 2014 at 09:51:57AM +0200, Peter Zijlstra wrote: > > I hope the assembly output I sent earlier helps, I'm afraid bisecting > > this could be painful. > > Yeah, lemme go have a look...
So I'm not seeing it, the cpus value is kept at -136(%rbp), so -128(%rbp) comes after and that's struct lb_env env. And -140(%rbp) comes before and that ends up being @idle. The compiler likes to spill for sure, but aside from stupid I don't see it doing wrong in the relatively short code from function start to the rep movsl. It does a rep stosl on -128(%rbp) and then fills it out, but none of that looks to stomp on our -136(%rbp) value. And the -140(%rbp) thing is only written to once, and while that is done after the 136 thing its a single movl and that's not going to clobber anything. And the fault happens before we pass @env around, so there no chance someone writes before it either. So I'm still entirely clueless.. -- 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/
