On 04/30/2013 08:08 PM, Steven Rostedt wrote: >> This NMI releated deadlock is a problem which should also trigger >> mainline, right? > > Well, yeah, as sending out a NMI stack dump is sorta the last resort, > and is dangerous to do printks from NMI context. So we did bad and we upgrade to bad and dangerous. >> >> Now, the time jump on the other hand is the real issue here and is >> RT-only. It looks like we get a big number of timer updates via >> tick_do_update_jiffies64() because according to ktime_get() that much >> time really passed by. > > As the NMI dump only happens because of the time jump, which as you > said, is -rt only, I wouldn't say that the NMI deadlock is a mainline > bug. The reason for the NMI was a bug in the -RT tree but if something else triggers that NMI we have a good chance to deadlock. What about a try_lock() and leave after 50 usecs of trying and not getting it in the in_nmi() case? > -- Steve Sebastian -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
