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.
