On Wed, Nov 12, 2014 at 9:20 AM, Oleg Nesterov <[email protected]> wrote: > Sorry, I am a bit confused... > > On 11/11, Borislav Petkov wrote: >> >> Roughly speaking, we want to be able to mark a task with the sign of >> death and to kill it, if needed. > > "it" is current, yes?
This part I'm not sure about due to MCE broadcast. "It" is current for exactly one cpu that's in do_machine_check. > > So I agree with Andy, task_work_add() can work and you can also pass > paddr/restartable to the handler. > > But, > >> The important part is *before* it >> gets to run again. > > But it is already running? Perhaps you meant "before it returns to > user-mode" ? > Right. But killing it in the do_exit sense from do_machine_check is currently impossible because do_machine_check runs on an IST stack. With my patch, if do_machine_check sees user_mode_vm(regs) and CONFIG_X86_64, then it will be running on the real task stack, so it can enable interrupts, kill the task however it wants, etc. This was the original motivation for my patch. --Andy -- 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/
