On Wed 2015-07-08 14:00:17, Steven Rostedt wrote: > On Wed, 08 Jul 2015 10:35:29 -0700 > Joe Perches <[email protected]> wrote: > > > On Wed, 2015-07-08 at 19:04 +0200, Luis R. Rodriguez wrote: > > > On Wed, Jul 08, 2015 at 05:08:35PM +0800, Gavin Hu wrote: > > > > Hi, > > > > > > > > Yes. We should disable the printk_limit feature when panic to avoid > > > > missing > > > > messages. > > > > > > Sounds like you have been looking into it and have a good idea of what you > > > want to do, why not try it and send some RFC patches ? > > > > > > While at it, then we could consider doing different things depending on > > > the > > > message type. KERN_EMERG would disable preemption, whereas KERN_INFO may > > > not be > > > so critical to require it. > > > > That might be a bit difficult to implement with complete correctness > > given KERN_EMERG use and continuation lines. > > > > Or just have the current context determine what to do. If printk() was > called with preemption or interrupts disabled, it flushes the full > buffer before returning, otherwise it allows the writes to console be > preempted.
I am afraid that any variant of this approach will make the original problem even worse. There will be more messages waiting and it will increase the chance of the softlockup. I guess that people call printk() with disabled interrupts or preemption with the naive hope that it will be fast (just store the message in the ring buffer and come back). I think that we really need to break the console output when it takes too long and schedule it somewhere else. Best Regards, Petr -- 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/
