On 10/03, Chuck Ebbert 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.
Ah, thanks, now I understand what you meant. I thought you meant switch_to(). Yes, I thought about this difference too, but so far I fail to understand how this can make a difference, according to calling.h it is callee-saved. Oleg. -- 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/
