On Mon, Dec 10, 2018 at 10:17 AM Steven Rostedt <rost...@goodmis.org> wrote: > > On Fri, 7 Dec 2018 17:51:19 +0800 > Feng Tang <feng.t...@intel.com> wrote: > > > When kernel panic happens, it will first print the panic call stack, > > then the ending msg like: > > > > [ 35.743249] ---[ end Kernel panic - not syncing: Fatal exception > > [ 35.749975] ------------[ cut here ]------------ > > > > The above message are very useful for debugging. > > > > But if system is configured to not reboot on panic, say the "panic_timeout" > > parameter equals 0, it will likely print out many noisy message like > > WARN() call stack for each and every CPU except the panic one, messages > > like below: > > > > Keeping the interrupt disabled will avoid the noisy message. > > > > When code runs to this point, it means user has chosed to not reboot, or > > do any special handling by using the panic notifier method, the only reason > > to enable the interrupt may be sysrq migic key and panic_blink function > > (though may not work even with irq enabled). > > > > So make the irq disabled by default and add a cmdline parameter > > "panic_keep_irq_on" to turn it on when needed. > > > > Signed-off-by: Feng Tang <feng.t...@intel.com> > > > > Acked-by: Steven Rostedt (VMware) <rost...@goodmis.org>
I'm fine with the new boot param, but I think we need to leave it how it was by default: systems that want to see the blinking aren't going to have a screen to read about what boot param they need to add. Currently, we'll blink and spew extra warnings. With this patch we'll not blink and not spew: a headless machine will have no indication that a panic happened. -Kees -- Kees Cook
