On Wed, Dec 3, 2014 at 12:19 PM, Dave Jones <[email protected]> wrote: > On Wed, Dec 03, 2014 at 12:06:56PM -0800, Andy Lutomirski wrote: > > > >> Did something in RCU change recently ? > > > > > > Not since -rc1, as far as I know, anyway. > > > > I have patches to delete this whole fscking sysret fast but not really > > fast path. I'll resend them for 3.19. In the mean time, can you test > > this patch by itself: > > > > > https://git.kernel.org/cgit/linux/kernel/git/luto/linux.git/commit/?h=x86/entry&id=1072a16a8d4ad1b11b8062f76e3236b9771b0fb6 > > With that applied, I no longer see the trace. >
Thanks. The bug is that SCHEDULE_USER in sysret_schedule is wrong. I'd suggest adding a warning to schedule_user that fires if context tracking thinks we're already in the kernel. FWIW, I think that the rest of the SCHEDULE_USER calls may be wrong, too. In particular, the one in int_careful looks wrong as well, so I don't see why my patch made a difference if I'm right. Frédéric, any ideas here? As a stopgap measure, making SCHEDULE_USER restore the previous state might make sense for 3.18. --Andy > thanks, > > Dave > -- Andy Lutomirski AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
