On 03/21/2012 06:18 PM, Corey Minyard wrote: > >> Look at drivers/char/ipmi/ipmi_msghandler.c. It has code to send panic >> event over IMPI. The code is pretty complex. Of course if we a going to >> implement something more complex than simple hypercall for panic >> notification we better do something more interesting with it than just >> saying "panic happened", like sending stack traces on all cpus for >> instance. > > I doubt that's the best example, unfortunately. The IPMI event log > has limited space and it has to be send a little piece at a time since > each log entry is 14 bytes. It just prints the panic string, nothing > else. Not that it isn't useful, it has saved my butt before. > > You have lots of interesting options with paravirtualization. You > could, for instance, create a console driver that delivered all > console output efficiently through a hypercall. That would be really > easy. Or, as you mention, a custom way to deliver panic information. > Collecting information like stack traces would be harder to > accomplish, as I don't think there is currently a way to get it except > by sending it to printk.
That already exists; virtio-console (or serial console emulation) can do the job. In fact the feature can be implemented 100% host side by searching for a panic string signature in the console logs. -- error compiling committee.c: too many arguments to function
