On Fri, Oct 3, 2014 at 3:48 PM, Chuck Ebbert <cebbert.l...@gmail.com> wrote: > On Fri, 3 Oct 2014 23:41:24 +0200 > Oleg Nesterov <o...@redhat.com> wrote: > >> On 10/03, Chuck Ebbert wrote: >> > >> > > [ 921.917752] ? ___preempt_schedule_context (arch/x86/lib/thunk_64.S:44) >> > > [ 921.917752] ? preempt_schedule_context (kernel/context_tracking.c:145) >> > > [ 921.917752] ? ___preempt_schedule_context (arch/x86/lib/thunk_64.S:44) >> > > [ 921.917752] ? preempt_schedule_context (kernel/context_tracking.c:145) >> > > [ 921.917752] ? ___preempt_schedule_context (arch/x86/lib/thunk_64.S:44) >> > > [ 921.917752] ? preempt_schedule_context (kernel/context_tracking.c:145) >> > > [ 921.917752] ? ___preempt_schedule_context (arch/x86/lib/thunk_64.S:44) >> > > [ 921.917752] ? preempt_schedule_context (kernel/context_tracking.c:145) >> > > [ 921.917752] ? ___preempt_schedule_context (arch/x86/lib/thunk_64.S:44) >> > > [ 921.917752] ? preempt_schedule_context (kernel/context_tracking.c:145) >> > >> > <snip lots of repeats of this> >> > >> > I *think* this is because RBP isn't being saved across task switch >> > anymore? >> > >> > Without CONFIG_FRAME_POINTERS that night not be a problem... >> >> Could you please spell? >> >> I don't even understand "RBP isn't being saved", SAVE_CONTEXT/RESTORE_CONTEXT >> do push/pop %rbp? >> > > SAVE_ARGS/RESTORE_ARGS, which is what THUNK uses, doesn't push/pop %rbp > > Before, SAVE_ALL/RESTORE_ALL were being used around the call to > preempt_schedule(). So from the symptoms I thought this was the problem.
rbp is callee-saved no matter what, unless my memory of the ABI is *waaaaay* off. --Andy -- 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/
