Wrote Oliver Yang Wrote: > Oliver Yang wrote: >> Oliver Yang wrote: >>> Colin Yi wrote: >>>> >>>> Oliver Yang Wrote: >>>>> Colin Yi wrote: >>>>>> >>>>>> Hi, >>>>>> We found a hard hang on a HP x86 system installed snv_130. >>>>>> firstly I add "set snooping=1" to /etc/system >>>>>> to try to get a core dump file. but it doesn't work, the system >>>>>> hang more than one hour and can't enter >>>>>> kmdb mode (the deadman timer is the default value). secondly I >>>>>> add?set pcpslump:apic_panic_on_nmi=1? to >>>>>> /etc/system, and send an NMI to OS from HP utility, The system >>>>>> enters the kmdb mode this time, But the keyboard >>>>>> freeze and I am not able to perform any operations in kmdb. >>>>>> >>>>>> Does anyone know any other way to debug this hard hang? >>>>>> >>>>> >>>>> Have you tied using kmdb via the tip line? Sometimes using tip >>>>> line is helpful. >>>> >>>> Doesn't work. >>> I'm little bit confused. >>> >>> The apic_panic_on_nmi should cause a system panic, have you seen >>> "NMI received" panic message on the console? >>> >> I meant, if you are loading kmdb with this option at same time, you >> can try to boot kernel without kmdb this time. Since >> apic_panic_on_nmi will trigger the code which will call panic routine >> directly, and this will not require any keyboard operation. >> > According to code of apic_nmi_intr, apic_panic_on_nmi will set > nopanicdebug which should prevent kernel to drop into kmdb. > > Have you set apic_kmdb_on_nmi flag? Your problem might be caused this > this flag, otherwise the nopanicdebug should let system panic directly. Yes, I set the apic_kmdb_on_nmi flag, I will try without it.
Thanks, Colin
