On Tue, Nov 17, 2015 at 06:07:08PM +0530, Vineet Gupta wrote: > On Tuesday 17 November 2015 05:52 PM, Peter Zijlstra wrote: > >> > BTW since we are on the topic we have this loop in stack unwinder which > >> > can > >> > potentially cause RCU stalls, actual lockups etc. I was planning to add > >> > the > >> > following - does that seem fine to you. > > Worries me more than anything. How could you get stuck in there? > > No we not getting stuck in there - but this has potential to - if say unwind > info > were corrupt (not seen that ever though).
Better put in a failsafe for that anyway, just out of sheer paranoia :-) You should never report more than PERF_MAX_STACK_DEPTH thingies anyway, so once you've done that many loops, you're good to bail, right? > The old code won't even respond to say a Ctrl+C if it were stuck ! > Plus the reschedule there will keeps sched happy when say unraveling deep > stack > frames with perf ? You're likely to call this code from interrupt/NMI context, there is no ^C or scheduling going to help you there. -- 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/
