From: Steven Rostedt > > Steven told me on Plumbers conference that even few initial > > characters saved him a day few times. > > Yes, and that has happened more than once. I would reboot and retest > code that is crashing, and due to a triple fault, the machine would > reboot because of some race, and the little output I get from the > console would help tremendously. > > Remember, debugging the kernel is a lot like forensics, especially when > it's from a customer's site. You look at all the evidence that you can > get, and sometimes it's just 10 characters in the output that gives you > an idea of where things went wrong. I'm really not liking the buffering > idea because of this. Yep, it is a real PITA that syslogd (or linux equiv) stops messages being written to the console by the kernel (which used to be synchronous) and instead writes them out from userspace. By that time it has all died. Sometimes you want a printk() that writes the data to the serial port before returning. I also spent a week trying to work out why a customer kernel was locking up - only to finally find out that the distro they were using set 'panic on opps' - making it almost impossible to find out what was happening. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
